Sample records for caii triplet spectroscopy

  1. A STIS Atlas of CaII Triplet Absorption Line Kinematics in Galactic Nuclei

    CERN Document Server

    Batcheldor, D; Valluri, M; Mandalou, J; Merritt, D


    The relations observed between supermassive black holes and their host galaxies suggest a fundamental link in the processes that cause these two objects to evolve. A more comprehensive understanding of these relations could be gained by increasing the number of supermassive black hole mass (M) measurements. This can be achieved, in part, by continuing to model the stellar dynamics at the centers of galactic bulges using data of the highest possible spatial resolution. Consequently, we present here an atlas of galaxies in the Space Telescope Imaging Spectrograph (STIS) data archive that may have spectra suitable for new M estimates. Archived STIS G750M data for all non-barred galactic bulges are co-aligned and combined, where appropriate, and the radial signal-to-noise ratios calculated. The line-of-sight velocity distributions from the CaII triplet are then determined using a maximum penalized likelihood method. We find 19 out of 42 galaxies may provide useful new M estimates since they are found to have data...

  2. Study of the Sextans dwarf spheroidal galaxy from the DART CaII triplet survey

    CERN Document Server

    Battaglia, G; Helmi, A; Irwin, M; Parisi, P; Hill, V; Jablonka, P


    We use VLT/FLAMES intermediate resolution (R~6500) spectra of individual red giant branch stars in the near-infrared CaII triplet (CaT) region to investigate the wide-area metallicity properties and internal kinematics of the Sextans dwarf spheroidal galaxy (dSph). Our final sample consists of 174 probable members of Sextans with accurate line-of-sight velocities (+- 2 km/s) and CaT [Fe/H] measurements (+- 0.2 dex). We use the MgI line at 8806.8 \\AA\\, as an empirical discriminator for distinguishing between probable members of the dSph (giant stars) and probable Galactic contaminants (dwarf stars). Sextans shows a similar chemo-dynamical behaviour to other Milky Way dSphs, with its central regions being more metal rich than the outer parts and with the more metal-rich stars displaying colder kinematics than the more metal-poor stars. Hints of a velocity gradient are found along the projected major axis and along an axis at P.A.=191 deg, however a larger and more spatially extended sample may be necessary to p...

  3. Study of the Sextans dwarf spheroidal galaxy from the DART CaII triplet survey

    NARCIS (Netherlands)

    Battaglia, G.; Tolstoy, E.; Helmi, A.; Irwin, M.; Parisi, P.; Hill, V.; Jablonka, P.


    We use Very Large Telescope (VLT)/Fibre Large Array Multi Element Spectrograph (FLAMES) intermediate-resolution (R similar to 6500) spectra of individual red giant branch stars in the near-infrared Ca ii triplet (CaT) region to investigate the wide-area metallicity properties and internal kinematics

  4. Triplet absorption spectroscopy and electromagnetically induced transparency (United States)

    Ghafoor, F.; Nazmitdinov, R. G.


    Coherence phenomena in a four-level atomic system, cyclically driven by three coherent fields, are investigated thoroughly at zero and weak magnetic fields. Each strongly interacting atomic state is converted to a triplet due to a dynamical Stark effect. Two dark lines with a Fano-like profile arise in the triplet absorption spectrum with anomalous dispersions. We provide conditions to control the widths of the transparency windows by means of the relative phase of the driving fields and the intensity of the microwave field, which closes the optical system loop. The effect of Doppler broadening on the results of the triplet absorption spectroscopy is analysed in detail.

  5. A new synthetic library of the Near-Infrared CaII triplet indices. I.Index Definition, Calibration and Relations with stellar atmospheric parameters

    CERN Document Server

    Du, Wei; Zhao, Yong-Heng


    Adopting the SPECTRUM package, we have synthesized a set of 2,890 Near-InfraRed (NIR) synthetic spectra with a resolution and wavelength sampling similar to the SDSS and the forthcoming LAMOST spectra. During the synthesis, we have applied the `New grids of ATLAS9 Model Atmosphere' to provide a grid of local thermodynamic equilibrium (LTE) model atmospheres. This synthetic stellar library is composed of 1,350 solor scaled abundance (SSA) and 1,530 non-solar scaled abundance (NSSA) spectra, grounding on which we have defined a new set of NIR CaII triplet indices and an index CaT as the sum of the three. Then, these defined indices have been automatically measured on the synthetic spectra and calibrated with the indices computed on the observational spectra from the INDO-U.S. stellar library. In order to check the effect of alpha-element enhancement on the so-defined CaII indices, we have compared indices measured on the SSA spectra with those on the NSSA ones at the same terns of stellar parameters (Teff, log ...

  6. Step-Scan FTIR spectroscopy and quantum chemical calculations of xanthone in the triplet state (United States)

    Buschhaus, L.; Kleinermanns, K.


    Step-Scan-FTIR spectroscopy has been used to measure the infrared spectrum of xanthone in the triplet state using chloroform as solvent. Xanthone is an important triplet sensitizer and therefore suitable as model system. Xanthone was excited at 266 nm and its IR triplet spectrum measured in the range 1000-1750 cm-1. The spectrum was analyzed by comparison with DFT/B3LYP/TZVP/COSMO calculations. Further on the results were compared to gas phase IR measurements of triplet xanthone and calculations of isolated xanthone. Mainly based on the calculations we tried to identify the geometry changes from the electronic ground state to the first triplet state.

  7. Precision spectroscopy with ultracold {sup 87}Rb{sub 2} triplet molecules

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Christoph


    In this thesis I report precision spectroscopy with ultracold {sup 87}Rb{sub 2} triplet molecules where we use lasers to couple the states in different molecular potentials. We study in detail states of the a {sup 3} sum {sup +}{sub u} and (1) {sup 3} sum {sup +}{sub g} potentials. These states are of great importance for transferring weakly bound molecules to the ro-vibrational triplet ground state via states of the excited potential. As most experiments start from molecules in their X {sup 1} sum {sup +}{sub g} ground state, the triplet states were hard to access via dipole transitions and remained largely unexplored. The measurements presented in this thesis are the first detailed study of diatomic {sup 87}Rb{sub 2} molecules in these states. Our experiments start with an ultracold cloud of {sup 87}Rb atoms. We then load this cloud into an optical lattice where we use a magnetic Feshbach resonance at 1007.4 G to perform a Feshbach association. After we have removed all unbound atoms, we end up with a pure sample of weakly bound Feshbach molecules inside the optical lattice. The optical lattice prevents these molecules from colliding with each other which results in molecular lifetimes on the order of a few hundred milliseconds. In the first set of experiments, we use a laser coupling the Feshbach state to the excited (1) {sup 3} sum {sup +}{sub g} triplet state to map out its low-lying vibrational (v = 0.. 15), rotational, hyperfine, and Zeeman structure. The experimental results are in good agreement with calculations done by Marius Lysebo and Prof. Leif Veseth. We then map out in detail the vibrational, rotational, hyperfine, and Zeeman structure of the a {sup 3} sum {sup +}{sub u} triplet ground state using dark state spectroscopy with levels in the (1) {sup 3} sum {sup +}{sub g} potential as an intermediate state. In this scheme we are able to access molecules in triplet states because our Feshbach state has strong triplet character. Interestingly, it

  8. Ordering of PCDTBT revealed by time-resolved electron paramagnetic resonance spectroscopy of its triplet excitons. (United States)

    Biskup, Till; Sommer, Michael; Rein, Stephan; Meyer, Deborah L; Kohlstädt, Markus; Würfel, Uli; Weber, Stefan


    Time-resolved electron paramagnetic resonance (TREPR) spectroscopy is shown to be a powerful tool to characterize triplet excitons of conjugated polymers. The resulting spectra are highly sensitive to the orientation of the molecule. In thin films cast on PET film, the molecules' orientation with respect to the surface plane can be determined, providing access to sample morphology on a microscopic scale. Surprisingly, the conjugated polymer investigated here, a promising material for organic photovoltaics, exhibits ordering even in bulk samples. Orientation effects may significantly influence the efficiency of solar cells, thus rendering proper control of sample morphology highly important.

  9. Autler-Townes triplet absorption spectroscopy, controllable electromagnetically induced transparency and nonlinear coherence Kerr effect

    CERN Document Server

    Bacha, Bakht Amin; Nazmidinov, Rashid G


    A Field Generated Coherence (FGC)' based 3-field cyclically-driven 4-level atomic system, which is an extended version of $\\Lambda$ type schemes, is investigated for Autler-Townes triplet absorption (ATT) spectroscopy. Two dark lines which appear in the ATT spectrum, are the essence of the generated multiple controllable EIT windows for a superluminal Gaussian light pulse. We also investigate enhancement in the group velocity for the Gaussian light pulse, using a nonlinear coherence Kerr effect. Consequently, the superluminal probing pulse leaves a steep anomalous region of the medium by $28 \\mu s$ sooner than the light pulse of the Kerr-free system. A co-linear propagation of the driving fields is suggested to minimize our explored Doppler broadening incoherence effect on the probe pulse. Indeed, the analytically observed undistorted retrieved light pulse, which is a necessary and useful requirement for realization of the results in laboratory, is also shown and analyzed explicitly.

  10. Ca II triplet spectroscopy of RGB stars in NGC 6822: kinematics and metallicities

    CERN Document Server

    Swan, Jesse; Tolstoy, Eline; Irwin, Mike J


    We present a detailed analysis of the chemistry and kinematics of red giants in the dwarf irregular galaxy NGC 6822. Spectroscopy at 8500 Angstroms was acquired for 72 red giant stars across two fields using FORS2 at the VLT. Line of sight extinction was individually estimated for each target star to accommodate the variable reddening across NGC 6822. The mean radial velocity was found to be v_helio = (52.8 +/- 2.2) km/s with dispersion rms = 24.1 km/s, in agreement with other studies. Ca II triplet equivalent widths were converted into [Fe/H] metallicities using a V magnitude proxy for surface gravity. The average metallicity was [Fe/H] = (-0.84 +/- 0.04) with dispersion rms = 0.31 dex and interquartile range 0.48. Our assignment of individual reddening values makes our analysis more sensitive to spatial variations in metallicity than previous studies. We divide our sample into metal-rich and metal-poor stars; the former are found to cluster towards small radii with the metal-poor stars more evenly distribut...

  11. Ca II triplet spectroscopy of RGB stars in NGC 6822: kinematics and metallicities (United States)

    Swan, J.; Cole, A. A.; Tolstoy, E.; Irwin, M. J.


    We present a detailed analysis of the chemistry and kinematics of red giants in the dwarf irregular galaxy NGC 6822. Spectroscopy at ≈8500 Å was acquired for 72 red giant stars across two fields using FORS2 at the VLT. Line-of-sight extinction was individually estimated for each target star to accommodate the variable reddening across NGC 6822. The mean radial velocity was found to be = -52.8 ± 2.2 km s-1 with dispersion σv = 24.1 km s-1, in agreement with other studies. Ca II triplet equivalent widths were converted into [Fe/H] metallicities using a V magnitude proxy for surface gravity. The average metallicity was = -0.84 ± 0.04 with dispersion σ = 0.31 dex and interquartile range 0.48. Our assignment of individual reddening values makes our analysis more sensitive to spatial variations in metallicity than previous studies. We divide our sample into metal-rich and metal-poor stars; the former were found to cluster towards small radii with the metal-poor stars more evenly distributed across the galaxy. The velocity dispersion of the metal-poor stars was found to be higher than that of the metal-rich stars (σ _{v_MP}=27.4 km s-1; σ _{v_MR}=21.1 km s-1); combined with the age-metallicity relation this indicates that the older populations have either been dynamically heated during their lifetimes or were born in a less disc-like distribution than the younger stars.. The low ratio vrot/σv suggests that within the inner 10 arcmin, NGC 6822's stars are dynamically decoupled from the H I gas, and possibly distributed in a thick disc or spheroid structure.

  12. Triplet exciton dissociation and electron extraction in graphene-templated pentacene observed with ultrafast spectroscopy. (United States)

    McDonough, Thomas J; Zhang, Lushuai; Roy, Susmit Singha; Kearns, Nicholas M; Arnold, Michael S; Zanni, Martin T; Andrew, Trisha L


    We compare the ultrafast dynamics of singlet fission and charge generation in pentacene films grown on glass and graphene. Pentacene grown on graphene is interesting because it forms large crystals with the long axis of the molecules "lying-down" (parallel to the surface). At low excitation fluence, spectra for pentacene on graphene contain triplet absorptions at 507 and 545 nm and no bleaching at 630 nm, which we show is due to the orientation of the pentacene molecules. We perform the first transient absorption anisotropy measurements on pentacene, observing negative anisotropy of the 507 and 545 nm peaks, consistent with triplet absorption. A broad feature at 853 nm, observed on both glass and graphene, is isotropic, suggesting hole absorption. At high fluence, there are additional features, whose kinetics and anisotropies are not explained by heating, that we assign to charge generation; we propose a polaron pair absorption at 614 nm. The lifetimes are shorter at high fluence for both pentacene on glass and graphene, indicative of triplet-triplet annihilation that likely enhances charge generation. The anisotropy decays more slowly for pentacene on graphene than on glass, in keeping with the smaller domain size observed via atomic force microscopy. Coherent acoustic phonons are observed for pentacene on graphene, which is a consequence of more homogeneous domains. Measuring the ultrafast dynamics of pentacene as a function of molecular orientation, fluence, and polarization provides new insight to previous spectral assignments.

  13. The spectroscopy of singlets and triplets excites electronic states, spatial and electronic structure of hydrocarbons and quantum classifications in chemmotology (United States)

    Obukhov, A. E.


    In this work we demonstrate the physical foundations of the spectroscopy of the grounds states: E- and X-ray, (RR) Raman scattering the NMR 1H and 13C and IR-, EPR- absorption and the singlets and triplets electronic excited states in the multinuclear hydrocarbons in chemmotology. The parameters of UV-absorption, RR-Raman scattering of light, the fluorescence and the phosphorescence and day-lasers at the pumping laser and lamp, OLEDs and OTETs- are measurements. The spectral-energy properties are briefly studied. The quantum-chemical LCAO-MO SCF expanded-CI PPP/S and INDO/S methods in the electronic and spatial structure hidrocarbons are considered.

  14. Deriving Metallicities from Calcium Triplet Spectroscopy in combination with Near Infrared Photometry

    CERN Document Server

    Mauro, F; Geisler, D; Saviane, I; Da Costa, G S; Gormaz-Matamala, A C; Vasquez, S; Chené, A -N; Cohen, R; Dias, B


    Context. [...] One of the most efficient methods is the measurement of the equivalent width (EW) of the Calcium II Triplet (CaT), corrected for the luminosity and temperature effects via magnitude differences from the horizontal branch (HB). Methods. We use the Ks magnitude difference between the star and the reddest part of the HB (RHB) to generate reduced equivalent widths (rEW) from the datasets presented in Saviane et al. (2012) and Rutledge et al. (1997). Subsequently we calibrated these rEW against three different metellicity (met) scales: the one presented in Carretta et al. (2009), the met values given in Harris (2010) and a version of the former corrected via high-resolution spectroscopic met. Results. We calculated the calibration relations for the two datasets and the three met scales and found that they are approximately equivalent, with differences almost negligible. We compared our nIR calibrations with the corresponding optical ones, and found them to be equivalent, establishing that the lumino...

  15. Characterization of the low-temperature triplet state of chlorophyll in photosystem II core complexes: Application of phosphorescence measurements and Fourier transform infrared spectroscopy. (United States)

    Zabelin, Alexey A; Neverov, Konstantin V; Krasnovsky, Alexander A; Shkuropatova, Valentina A; Shuvalov, Vladimir A; Shkuropatov, Anatoly Ya


    Phosphorescence measurements at 77 K and light-induced FTIR difference spectroscopy at 95 K were applied to study of the triplet state of chlorophyll a ((3)Chl) in photosystem II (PSII) core complexes isolated from spinach. Using both methods, (3)Chl was observed in the core preparations with doubly reduced primary quinone acceptor QA. The spectral parameters of Chl phosphorescence resemble those in the isolated PSII reaction centers (RCs). The main spectral maximum and the lifetime of the phosphorescence corresponded to 955±1 nm and of 1.65±0.05 ms respectively; in the excitation spectrum, the absorption maxima of all core complex pigments (Chl, pheophytin a (Pheo), and β-carotene) were observed. The differential signal at 1667(-)/1628(+)cm(-1) reflecting a downshift of the stretching frequency of the 13(1)-keto C=O group of Chl was found to dominate in the triplet-minus-singlet FTIR difference spectrum of core complexes. Based on FTIR results and literature data, it is proposed that (3)Chl is mostly localized on the accessory chlorophyll that is in triplet equilibrium with P680. Analysis of the data suggests that the Chl triplet state responsible for the phosphorescence and the FTIR difference spectrum is mainly generated due to charge recombination in the reaction center radical pair P680(+)PheoD1(-), and the energy and temporal parameters of this triplet state as well as the molecular environment and interactions of the triplet-bearing Chl molecule are similar in the PSII core complexes and isolated PSII RCs.

  16. Dynamics of water-alcohol mixtures: Insights from nuclear magnetic resonance, broadband dielectric spectroscopy, and triplet solvation dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Sauer, D.; Schuster, B.; Rosenstihl, M.; Schneider, S.; Blochowicz, T.; Stühn, B.; Vogel, M. [Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt (Germany); Talluto, V.; Walther, T. [Institut für Angewandte Physik, Technische Universität Darmstadt, Schlossgartenstraße 7, 64289 Darmstadt (Germany)


    We combine {sup 2}H nuclear magnetic resonance (NMR), broadband dielectric spectroscopy (BDS), and triplet solvation dynamics (TSD) to investigate molecular dynamics in glass-forming mixtures of water and propylene glycol in very broad time and temperature ranges. All methods yield consistent results for the α process of the studied mixtures, which hardly depends on the composition and shows Vogel-Fulcher temperature dependence as well as Cole-Davidson spectral shape. The good agreement between BDS and TDS data reveals that preferential solvation of dye molecules in microheterogeneous mixtures does not play an important role. Below the glass transition temperature T{sub g}, NMR and BDS studies reveal that the β process of the mixtures shows correlation times, which depend on the water concentration, but exhibit a common temperature dependence, obeying an Arrhenius law with an activation energy of E{sub a} = 0.54  eV, as previously reported for mixtures of water with various molecular species. Detailed comparison of NMR and BDS correlation functions for the β process unravels that the former decay faster and more stretched than the latter. Moreover, the present NMR data imply that propylene glycol participates in the β process and, hence, it is not a pure water process, and that the mechanism for molecular dynamics underlying the β process differs in mixtures of water with small and large molecules.

  17. Ca II Triplet Spectroscopy of Small Magellanic Cloud Red Giants. III. Abundances and Velocities for a Sample of 14 Clusters

    CERN Document Server

    Parisi, M C; Clariá, J J; Villanova, S; Marcionni, N; Sarajedini, A; Grocholski, A J


    We obtained spectra of red giants in 15 Small Magellanic Cloud (SMC) clusters in the region of the CaII lines with FORS2 on the Very Large Telescope (VLT). We determined the mean metallicity and radial velocity with mean errors of 0.05 dex and 2.6 km/s, respectively, from a mean of 6.5 members per cluster. One cluster (B113) was too young for a reliable metallicity determination and was excluded from the sample. We combined the sample studied here with 15 clusters previously studied by us using the same technique, and with 7 clusters whose metallicities determined by other authors are on a scale similar to ours. This compilation of 36 clusters is the largest SMC cluster sample currently available with accurate and homogeneously determined metallicities. We found a high probability that the metallicity distribution is bimodal, with potential peaks at -1.1 and -0.8 dex. Our data show no strong evidence of a metallicity gradient in the SMC clusters, somewhat at odds with recent evidence from CaT spectra of a lar...

  18. CaII Κ Imaging to Understand UV Irradiance Variability

    Indian Academy of Sciences (India)

    R. Kariyappa


    To identify and understand the underlying physical mechanisms of total solar and UV irradiance variability and to estimate the contribution of various chromospheric features to UV irradiance, detailed analysis of spatially resolved data is required. The various chromospheric features have been segregated and different parameters have been derived from CaII Κ Spectroheliograms of NSO/Sac Peak and Kodaikanal Observatory and compared with UV irradiance flux measured in MgII h and k lines by NOAA 9 satellite. The important results of this detailed analysis of CaII Κ Images of 1992 together with UV irradiance data will be discussed in this paper.

  19. Identification of the sites of chlorophyll triplet quenching in relation to the structure of LHC-II from higher plants. Evidence from EPR spectroscopy. (United States)

    Di Valentin, Marilena; Biasibetti, Federico; Ceola, Stefano; Carbonera, Donatella


    The Chlorophyll a (Chl a) molecules involved in the triplet-triplet energy transfer to the central luteins in trimeric LHC-II are identified by time-resolved and pulse EPR techniques. The concept of spin angular momentum conservation during triplet-triplet energy transfer is exploited for the calculation of the spin polarization of the carotenoid triplet states. The sites with the highest probability of forming triplet states, which are quenched by the central luteins, result to be Chl603 and Chl612. "Unquenched" Chl triplet states are produced by photoexcitation in the LHC-II complex. Putative sites of these triplet states are Chl614, Chl611, Chl604, and Chl613 since they do not contribute to the formation of the observed carotenoid triplet states.

  20. Time-resolved photoelectron spectroscopy of a dinuclear Pt(II) complex: Tunneling autodetachment from both singlet and triplet excited states of a molecular dianion (United States)

    Winghart, Marc-Oliver; Yang, Ji-Ping; Vonderach, Matthias; Unterreiner, Andreas-Neil; Huang, Dao-Ling; Wang, Lai-Sheng; Kruppa, Sebastian; Riehn, Christoph; Kappes, Manfred M.


    Time-resolved pump-probe photoelectron spectroscopy has been used to study the relaxation dynamics of gaseous [Pt2(μ-P2O5H2)4 + 2H]2- after population of its first singlet excited state by 388 nm femtosecond laser irradiation. In contrast to the fluorescence and phosphorescence observed in condensed phase, a significant fraction of the photoexcited isolated dianions decays by electron loss to form the corresponding monoanions. Our transient photoelectron data reveal an ultrafast decay of the initially excited singlet 1A2u state and concomitant rise in population of the triplet 3A2u state, via sub-picosecond intersystem crossing (ISC). We find that both of the electronically excited states are metastably bound behind a repulsive Coulomb barrier and can decay via delayed autodetachment to yield electrons with characteristic kinetic energies. While excited state tunneling detachment (ESETD) from the singlet 1A2u state takes only a few picoseconds, ESETD from the triplet 3A2u state is much slower and proceeds on a time scale of hundreds of nanoseconds. The ISC rate in the gas phase is significantly higher than in solution, which can be rationalized in terms of changes to the energy dissipation mechanism in the absence of solvent molecules. [Pt2(μ-P2O5H2)4 + 2H]2- is the first example of a photoexcited multianion for which ESETD has been observed following ISC.

  1. Confirming the intrinsic abundance spread in the globular cluster NGC 6273 (M 19) with calcium triplet spectroscopy

    CERN Document Server

    Yong, David; Norris, John E


    We present metallicities for red giant stars in the globular cluster NGC 6273 based on intermediate resolution GMOS-S spectra of the calcium triplet region. For the 42 radial velocity members with reliable calcium triplet line strength measurements, we obtain metallicities, [Fe/H], using calibrations established from standard globular clusters. We confirm the presence of an intrinsic abundance dispersion identified by Johnson et al. (2015). The total range in [Fe/H] is ~1.0 dex and after taking into account the measurement errors, the intrinsic abundance dispersion is \\sigma[Fe/H] = 0.17 dex. Among the Galactic globular clusters, the abundance dispersion in NGC 6273 is only exceeded by omega Cen, which is regarded as the remnant of a disrupted dwarf galaxy, and M 54, which is the nuclear star cluster of the Sagittarius dwarf galaxy. If these three globular clusters share the same formation mechanism, then NGC 6273 may also be the remnant nucleus of a disrupted dwarf galaxy.

  2. Confirming the intrinsic abundance spread in the globular cluster NGC 6273 (M19) with calcium triplet spectroscopy (United States)

    Yong, David; Da Costa, Gary S.; Norris, John E.


    We present metallicities for red giant stars in the globular cluster NGC 6273 based on intermediate resolution GMOS-S spectra of the calcium triplet region. For the 42 radial velocity members with reliable calcium triplet line strength measurements, we obtain metallicities, [Fe/H], using calibrations established from standard globular clusters. We confirm the presence of an intrinsic abundance dispersion identified by Johnson et al. The total range in [Fe/H] is ˜1.0 dex and after taking into account the measurement errors, the intrinsic abundance dispersion is σint[Fe/H] = 0.17 dex. Among the Galactic globular clusters, the abundance dispersion in NGC 6273 is only exceeded by ω Cen, which is regarded as the remnant of a disrupted dwarf galaxy, and M54, which is the nuclear star cluster of the Sagittarius dwarf galaxy. If these three globular clusters share the same formation mechanism, then NGC 6273 may also be the remnant nucleus of a disrupted dwarf galaxy.

  3. Time-resolved photoelectron spectroscopy of a dinuclear Pt(II) complex: Tunneling autodetachment from both singlet and triplet excited states of a molecular dianion

    Energy Technology Data Exchange (ETDEWEB)

    Winghart, Marc-Oliver, E-mail:; Unterreiner, Andreas-Neil [Institute of Physical Chemistry, Karlsruhe Institute of Technology, P.O. Box 6980, 76049 Karlsruhe (Germany); Yang, Ji-Ping [Institute of Physical Chemistry, Karlsruhe Institute of Technology, P.O. Box 6980, 76049 Karlsruhe (Germany); School of Sciences, Hefei University of Technology, Hefei 230009 (China); Vonderach, Matthias [Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB (United Kingdom); Huang, Dao-Ling; Wang, Lai-Sheng [Department of Chemistry, Brown University, Providence, Rhode Island 02912 (United States); Kruppa, Sebastian; Riehn, Christoph [Fachbereich Chemie und Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Kappes, Manfred M., E-mail: [Institute of Physical Chemistry, Karlsruhe Institute of Technology, P.O. Box 6980, 76049 Karlsruhe (Germany); Institute of Nanotechnology, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe (Germany)


    Time-resolved pump-probe photoelectron spectroscopy has been used to study the relaxation dynamics of gaseous [Pt{sub 2}(μ-P{sub 2}O{sub 5}H{sub 2}){sub 4} + 2H]{sup 2−} after population of its first singlet excited state by 388 nm femtosecond laser irradiation. In contrast to the fluorescence and phosphorescence observed in condensed phase, a significant fraction of the photoexcited isolated dianions decays by electron loss to form the corresponding monoanions. Our transient photoelectron data reveal an ultrafast decay of the initially excited singlet {sup 1}A{sub 2u} state and concomitant rise in population of the triplet {sup 3}A{sub 2u} state, via sub-picosecond intersystem crossing (ISC). We find that both of the electronically excited states are metastably bound behind a repulsive Coulomb barrier and can decay via delayed autodetachment to yield electrons with characteristic kinetic energies. While excited state tunneling detachment (ESETD) from the singlet {sup 1}A{sub 2u} state takes only a few picoseconds, ESETD from the triplet {sup 3}A{sub 2u} state is much slower and proceeds on a time scale of hundreds of nanoseconds. The ISC rate in the gas phase is significantly higher than in solution, which can be rationalized in terms of changes to the energy dissipation mechanism in the absence of solvent molecules. [Pt{sub 2}(μ-P{sub 2}O{sub 5}H{sub 2}){sub 4} + 2H]{sup 2−} is the first example of a photoexcited multianion for which ESETD has been observed following ISC.


    Energy Technology Data Exchange (ETDEWEB)

    Parisi, M. C.; Clariá, J. J.; Marcionni, N. [Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, Córdoba, CP 5000 (Argentina); Geisler, D.; Villanova, S. [Departamento de Astronomía, Universidad de Concepción Casilla 160-C, Concepción (Chile); Sarajedini, A. [Department of Astronomy, University of Florida P.O. Box 112055, Gainesville, FL 32611 (United States); Grocholski, A. J., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Department of Physics and Astronomy, Louisiana State University 202 Nicholson Hall, Tower Drive, Baton Rouge, LA 70803-4001 (United States)


    We obtained spectra of red giants in 15 Small Magellanic Cloud (SMC) clusters in the region of the Ca ii lines with FORS2 on the Very Large Telescope. We determined the mean metallicity and radial velocity with mean errors of 0.05 dex and 2.6 km s{sup −1}, respectively, from a mean of 6.5 members per cluster. One cluster (B113) was too young for a reliable metallicity determination and was excluded from the sample. We combined the sample studied here with 15 clusters previously studied by us using the same technique, and with 7 clusters whose metallicities determined by other authors are on a scale similar to ours. This compilation of 36 clusters is the largest SMC cluster sample currently available with accurate and homogeneously determined metallicities. We found a high probability that the metallicity distribution is bimodal, with potential peaks at −1.1 and −0.8 dex. Our data show no strong evidence of a metallicity gradient in the SMC clusters, somewhat at odds with recent evidence from Ca ii triplet spectra of a large sample of field stars. This may be revealing possible differences in the chemical history of clusters and field stars. Our clusters show a significant dispersion of metallicities, whatever age is considered, which could be reflecting the lack of a unique age–metallicity relation in this galaxy. None of the chemical evolution models currently available in the literature satisfactorily represents the global chemical enrichment processes of SMC clusters.

  5. Spectroscopy of {sup 39}K{sup 85}Rb triplet excited states using ultracold a {sup 3}{sigma}{sup +} state molecules formed by photoassociation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J T; Wang, D; Eyler, E E; Gould, P L; Stwalley, W C [Physics Department, University of Connecticut, Storrs, CT 06269 (United States)], E-mail:, E-mail:


    Convenient state-selective detection methods are proposed for exploring triplet Rydberg states from the metastable a {sup 3}{sigma}{sup +} state of ultracold KRb molecules by resonance-enhanced two-photon ionization and time-of-flight (TOF) mass spectroscopy. This would allow the first accurate determination of the ionization potential. Particularly suitable resonant intermediate states include the 2 {sup 3}{pi} {sub {omega}}, 3 {sup 3}{sigma}{sup +} and 4 {sup 3}{sigma}{sup +} states, and we report spectroscopic studies of these states. For the 2 {sup 3}{pi} {sub {omega}} state, the spin-orbit components ({omega} = 0{sup +}, 0{sup -}, 1 and 2) have been investigated and a shallow long-range state (5(0{sup +})) at {approx} 9.3 A has been observed. We compare our observations of these three states with predictions based on ab initio potential energy curves. Such studies may also permit the direct observation of autoionizing resonances leading to efficient formation of low-lying rovibrational levels of the {sup 2}{sigma}{sup +} ground state of KRb{sup +}, ideally in the v{sup +}= 0, N{sup +}= 0 level.

  6. Vibrational circular dichroism spectroscopy of a spin-triplet bis-(biuretato) cobaltate(III) coordination compound with low-lying electronic transitions. (United States)

    Johannessen, Christian; Thulstrup, Peter W


    Vibrational absorption (VA) and vibrational circular dichroism (VCD) spectroscopy was applied in the analysis of vibrational and low lying electronic transitions of a triplet ground state cobalt(III) coordination compound. The spectroscopic measurements were performed on the tetrabutylammonium salt of (6S,7S)-1,3,5,8,10,12-hexaaza-2,4,9,11-tetraoxo-6,7-diphenyl-dodecanato(4-)cobaltate(III) in DMSO solution and in potassium bromide pellets. The chiral anion exhibits an unusual geometry for cobalt(III), being four-coordinate, planar, and paramagnetic with an intermediate spin state. The spectroscopic results were compared to measurements performed on the free ligand and to theoretical calculations using density functional theory (B3LYP/TZVP). The results of the VCD analysis of the coordination compound identified an electronic, dipole-forbidden, magnetic dipole-allowed low-lying d-d transition located in the mid infrared, as well as several amide stretch transitions located in the fingerprint region (1800-1100 cm(-1)), in both the liquid and solid phase. VCD signals were found to be 5-10 times higher than expected, indicating enhancement of the vibrational CD signals, caused by coupling of the vibrational transitions with the close-lying electronic transition.

  7. Radial velocities and metallicities from infrared Ca II triplet spectroscopy of open clusters II. Berkeley 23, King 1, NGC 559, NGC 6603 and NGC 7245

    CERN Document Server

    Carrera, R; Ospina, N; Balaguer-Nuñez, L; Jordi, C; Monteagudo, L


    Context: Open clusters are key to studying the formation and evolution of the Galactic disc. However, there is a deficiency of radial velocity and chemical abundance determinations for open clusters in the literature. Aims: We intend to increase the number of determinations of radial velocities and metallicities from spectroscopy for open clusters. Methods: We acquired medium-resolution spectra (R~8000) in the infrared region Ca II triplet lines (~8500 AA) for several stars in five open clusters with the long-slit IDS spectrograph on the 2.5~m Isaac Newton Telescope (Roque de los Muchachos Observatory, Spain). Radial velocities were obtained by cross-correlation fitting techniques. The relationships available in the literature between the strength of infrared Ca II lines and metallicity were also used to derive the metallicity for each cluster. Results: We obtain = 48.6+/-3.4, -58.4+/-6.8, 26.0+/-4.3 and -65.3+/-3.2 km s-1 for Berkeley 23, NGC 559, NGC 6603 and NGC 7245, respectively. We found [Fe/H] =-0.25+...

  8. The Infrared Ca II triplet as metallicity indicator

    CERN Document Server

    Carrera, Ricardo; Pancino, Elena; Zinn, Robert


    From observations of almost 500 RGB stars in 29 Galactic open and globular clusters, we have investigated the behaviour of the infrared Ca II triplet (8498, 8542 and 8662 \\AA) in the age range 13$\\leq$Age/Gyr$\\leq$0.25 and the metallicity range $-2.2\\leq$ [Fe/H] $\\leq$+0.47. These are the widest ranges of ages and metallicities in which the behaviour of the Ca II triplet lines has been investigated in a homogeneous way. We report the first empirical study of the variation of the CaII triplet lines strength, for given metallicities, with respect to luminosity. We find that the sequence defined by each cluster in the Luminosity-$\\Sigma$Ca plane is not exactly linear. However, when only stars in a small magnitude interval are observed, the sequences can be considered as linear. We have studied the the Ca II triplet lines on three metallicities scales. While a linear correlation between the reduced equivalent width ($W'_V$ or $W'_I$) versus metallicity is found in the \\citet{cg97} and \\citet{ki03} scales, a secon...

  9. Investigation of the lowest triplet state of the pyrochlorophyllide a-apomyoglobin complex by zero-field optically detected magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, R.H. (Boston Univ., MA); Hanlon, E.B.; Boxer, S.G.


    The zero-field fluorescence-detected triplet state magnetic resonance spectra have been obtained for the pyrochlorophyllide a-apomyoglobin complex at 2 K. The triplet state zero-field splittings and spin sublevel dynamics were detected on the resolved features of the structured low-temperature fluorescence. Structured fluorescence is not observed for pyrochlorophyllide a in an organic matrix under identical conditions. These data are interpreted in terms of the local binding site of the pyrochlorophyllide a chromophore in the protein and the low-temperature conformation of the protein matrix. 15 references, 1 figure, 1 table.

  10. 激变变星及相关天体的与近红外电离钙三重线的光谱分析%Spectroscopy around and Ca II Triplet of Cataclysmic Variables and Related Objects

    Institute of Scientific and Technical Information of China (English)

    刘学富; 陈阳; 黄河


    给出了1997年4月15日至17日在北京天文台用2.16 m望远镜卡焦光谱仪观测获得的6颗激变变星 (AB Boo, UX UMa, T CrB, AH Her, Z Cam 和 V426 Oph) 及3颗相关天体(UMa3, EG UMa 和 Leo3)的CCD光谱, 并同时拍摄了5颗晚型星(3 Dra, Vir, Leo, 34 Boo 和36Com) 的CCD 光谱, 作为晚型星参考谱. 测量了观测样本星的和近红外Ca II的三重线(8498, 8542和 8662)的等值宽度(EW),谱线半极大全宽(FWHM)和视向速度(Vr), 并分析了这些星的活动性.%In this paper, some CCD spectra of 6 cataclysmic variables: AB Boo, T CrB, UX UMa, AH Her, Z Cam, V426 Oph and 3 related objects: Leo3, UMa3 and EG UMa are presented. We also observed 5 late-type stars: 3 Dra, Vir, Leo, 34 Boo, and 36 Com in order to provide comparison with the late-type component of the program systems. The observations were made using the 2.16 m telescope of Bejing Observatory with a Cassergrain spectrograph on 1997—04—15/17 at the Xinglong Station. The CCD spectra were obtained with a low resolution and a dispersion of 1.2/pixel. The spectral region covered is from 5920 to 7072, and from 7950 to 9180 for all the program stars and only 3390—8380 for AH Her. Representative spectra are given for each object. The equivalent width (EW) and FWHM of and CaII triplet lines were determined. The radial velocities for 9 program stars were also determined. Implications of our results are discussed.


    NARCIS (Netherlands)

    Leaman, Ryan; Cole, Andrew A.; Venn, Kim A.; Tolstoy, Eline; Irwin, Mike J.; Szeifert, Thomas; Skillman, Evan D.; McConnachie, Alan W.


    We present the first determination of the radial velocities and metallicities of 78 red giant stars in the isolated dwarf irregular galaxy WLM. Observations of the calcium II triplet in these stars were made with FORS2 at the VLT-UT2 in two separated fields of view in WLM, and the [Fe/H] values were

  12. Toward Triplet Ground State NaLi Molecules (United States)

    Ebadi, Sepehr; Jamison, Alan; Rvachov, Timur; Jing, Li; Son, Hyungmok; Jiang, Yijun; Zwierlein, Martin; Ketterle, Wolfgang


    The NaLi molecule is expected to have a long lifetime in the triplet ground-state due to its fermionic nature, large rotational constant, and weak spin-orbit coupling. The triplet state has both electric and magnetic dipole moments, affording unique opportunities in quantum simulation and ultracold chemistry. We have mapped the excited state NaLi triplet potential by means of photoassociation spectroscopy. We report on this and our further progress toward the creation of the triplet ground-state molecules using STIRAP. NSF, ARO-MURI, Samsung, NSERC.

  13. Negative regulation of NaF-induced apoptosis by Bad-CAII complex. (United States)

    Otsuki, S; Sugiyama, K; Amano, O; Yasui, T; Sakagami, H


    Fluoride is used to prevent caries in dentistry. However, its mechanism of cytotoxicity induction is unclear. This study was undertaken to determine whether sodium fluoride (NaF) induces apoptosis in human oral cells and if so, whether Bad protein is involved in the process. NaF showed higher cytotoxicity and apoptosis-inducing activity against human oral squamous cell carcinoma cells (HSC-2) than against human gingival fibroblasts (HGF). Western blot analysis showed that NaF enhanced the expression and dephosphorylation of Bad protein. This study demonstrates for the first time that Bad protein forms a complex with carbonic anhydrase II (CAII), and NaF stimulates the detachment of CAII from the Bad-CAII complex and the replacement by the formation of Bad-Bcl-2 complex. Knockdown of Bad and CAII mRNA by siRNA inhibited and enhanced the NaF-induced caspase activation, respectively. The present study suggests that CAII negatively regulates the NaF-induced apoptosis by forming a complex with Bad.

  14. Triplet-triplet energy transfer from chlorophylls to carotenoids in two antenna complexes from dinoflagellate Amphidinium carterae. (United States)

    Kvíčalová, Zuzana; Alster, Jan; Hofmann, Eckhard; Khoroshyy, Petro; Litvín, Radek; Bína, David; Polívka, Tomáš; Pšenčík, Jakub


    Room temperature transient absorption spectroscopy with nanosecond resolution was used to study quenching of the chlorophyll triplet states by carotenoids in two light-harvesting complexes of the dinoflagellate Amphidinium carterae: the water soluble peridinin-chlorophyll protein complex and intrinsic, membrane chlorophyll a-chlorophyll c2-peridinin protein complex. The combined study of the two complexes facilitated interpretation of a rather complicated relaxation observed in the intrinsic complex. While a single carotenoid triplet state was resolved in the peridinin-chlorophyll protein complex, evidence of at least two different carotenoid triplets was obtained for the intrinsic light-harvesting complex. Most probably, each of these carotenoids protects different chlorophylls. In both complexes the quenching of the chlorophyll triplet states by carotenoids occurs with a very high efficiency (~100%), and with transfer times estimated to be in the order of 0.1ns or even faster. The triplet-triplet energy transfer is thus much faster than formation of the chlorophyll triplet states by intersystem crossing. Since the triplet states of chlorophylls are formed during the whole lifetime of their singlet states, the apparent lifetimes of both states are the same, and observed to be equal to the carotenoid triplet state rise time (~5ns).

  15. Type I photosensitized reactions of oxopurines. Kinetics and thermodynamics of the reaction with triplet benzophenone by time-resolved photoacoustic spectroscopy (United States)

    Murgida, Daniel H.; Erra Balsells, Rosa; Crippa, Pier Raimondo; Viappiani, Cristiano


    Benzophenone photosensitized reactions of caffeine, theophylline and theobromine were investigated in acetonitrile by time-resolved laser-induced photoacoustics. In the three cases global quenching rate constants of triplet benzophenone were measured as a function of temperature and it was observed that this is a non-activated process. Besides, for theobromine and theophylline heats for NH hydrogen abstraction reactions were determined. In agreement with semiempirical calculation predictions, hydrogen abstraction is thermodynamically more favorable and faster for theophylline (Δ H=-265 kJ mol -1, kr=9.6×10 8 M -1 s -1) than for theobromine (Δ H=-168 kJ mol -1, kr=3.7×10 8 M -1 s -1).

  16. Role of MCT1 and CAII in skeletal muscle pH homeostasis, energetics, and function: in vivo insights from MCT1 haploinsufficient mice

    KAUST Repository

    Chatel, Benjamin


    The purpose of this study was to investigate the effects of a partial suppression of monocarboxylate transporter (MCT)-1 on skeletal muscle pH, energetics, and function (MCT1(+/-) mice). Twenty-four MCT1(+/-) and 13 wild-type (WT) mice were subjected to a rest-exercise-recovery protocol, allowing assessment of muscle energetics (by magnetic resonance spectroscopy) and function. The study included analysis of enzyme activities and content of protein involved in pH regulation. Skeletal muscle of MCT1(+/-) mice had lower MCT1 (-61%; P < 0.05) and carbonic anhydrase (CA)-II (-54%; P < 0.05) contents. Although intramuscular pH was higher in MCT1(+/-) mice at rest (P < 0.001), the mice showed higher acidosis during the first minute of exercise (P < 0.01). Then, the pH time course was similar among groups until exercise completion. MCT1(+/-) mice had higher specific peak (P < 0.05) and maximum tetanic (P < 0.01) forces and lower fatigability (P < 0.001) when compared to WT mice. We conclude that both MCT1 and CAII are involved in the homeostatic control of pH in skeletal muscle, both at rest and at the onset of exercise. The improved muscle function and resistance to fatigue in MCT1(+/-) mice remain unexplained.-Chatel, B., Bendahan, D., Hourdé, C., Pellerin, L., Lengacher, S., Magistretti, P., Fur, Y. L., Vilmen, C., Bernard, M., Messonnier, L. A. Role of MCT1 and CAII in skeletal muscle pH homeostasis, energetics, and function: in vivo insights from MCT1 haploinsufficient mice.

  17. The unimolecular reaction of t-BuNO on singlet and triplet surfaces: Spectroscopy, real-time rate measurements, and NO energy distributions (United States)

    Noble, M.; Qian, C. X. W.; Reisler, H.; Wittig, C.


    The predissociation of jet-cooled (CH3)3CNO (t-BuNO) following laser excitation in the à 1A`←X˜ 1A' system has been studied in both the energy (frequency) and time domains. Unlike the smaller nitroso compounds whose predissociation has been already examined, unimolecular reaction is the rate determining step for predissociation near threshold. Consequently, it has been possible to separately measure radiationless transition rates and unimolecular reaction rates in real time. Dissociation on both the ground state (S0) and the first triplet state (T1) has been identified. At threshold, dissociation proceeds only on S0, with lifetimes >3.5 μs, but for E°≥650 cm-1, fast (<10 ns) predissociation via T1 becomes progressively the dominant dissociative route. Nascent NO photofragments have been characterized in detail using one-photon LIF. The rotational and spin-orbit distributions of NO following dissociation on S0 are statistical, depending only on E°. The NO derived from dissociation on the T1 surface is not at all statistical, consistent with a sizable (˜650 cm-1) exit channel barrier on this surface. Most notably, the [NO(2Π3/2)]/[NO(2Π1/2)] ratios are much smaller, and rotational distributions are colder than predicted by a statistical model. In order that some of the predissociating vibrational states could be assigned, the 1A`←1A' spectrum of t-BuNO has been analyzed and the electronic origin assigned as 13 911 cm-1. The ground state dissociation energy, D0, is found to be 13 930±30 cm-1, i.e., 39.8±0.1 kcal mol-1.

  18. Ca II Triplet Spectroscopy of Small Magellanic Cloud Red Giants. IV. Abundances for a Large Sample of Field Stars and Comparison with the Cluster Sample (United States)

    Parisi, M. C.; Geisler, D.; Carraro, G.; Clariá, J. J.; Villanova, S.; Gramajo, L. V.; Sarajedini, A.; Grocholski, A. J.


    This paper represents a major step forward in the systematic and homogeneous study of Small Magellanic Cloud (SMC) star clusters and field stars carried out by applying the calcium triplet technique. We present in this work the radial velocity and metallicity of approximately 400 red giant stars in 15 SMC fields, with typical errors of about 7 km s-1 and 0.16 dex, respectively. We added to this information our previously determined metallicity values for 29 clusters and approximately 350 field stars using the identical techniques. Using this enlarged sample, we analyze the metallicity distribution and gradient in this galaxy. We also compare the chemical properties of the clusters and of their surrounding fields. We find a number of surprising results. While the clusters, taken as a whole, show no strong evidence for a metallicity gradient (MG), the field stars exhibit a clear negative gradient in the inner region of the SMC, consistent with the recent results of Dobbie et al. For distances to the center of the galaxy less than 4°, field stars show a considerably smaller metallicity dispersion than that of the clusters. However, in the external SMC regions, clusters and field stars exhibit similar metallicity dispersions. Moreover, in the inner region of the SMC, clusters appear to be concentrated in two groups: one more metal-poor and another more metal-rich than field stars. Individually considered, neither cluster group presents an MG. Most surprisingly, the MG for both stellar populations (clusters and field stars) appears to reverse sign in the outer regions of the SMC. The difference between the cluster metallicity and the mean metallicity of the surrounding field stars turns out to be a strong function of the cluster metallicity. These results could be indicating different chemical evolution histories for these two SMC stellar populations. They could also indicate variations in the chemical behavior of the SMC in its internal and external regions.

  19. Lowest triplet (n, π*) electronic state of acrolein: Determination of structural parameters by cavity ringdown spectroscopy and quantum-chemical methods (United States)

    Hlavacek, Nikolaus C.; McAnally, Michael O.; Drucker, Stephen


    The cavity ringdown absorption spectrum of acrolein (propenal, CH2=CH—CH=O) was recorded near 412 nm, under bulk-gas conditions at room temperature and in a free-jet expansion. The measured spectral region includes the 0^0_0 band of the T1(n, π*) ← S0 system. We analyzed the 0^0_0 rotational contour by using the STROTA computer program [R. H. Judge et al., J. Chem. Phys. 103, 5343 (1995)], 10.1063/1.470569, which incorporates an asymmetric rotor Hamiltonian for simulating and fitting singlet-triplet spectra. We used the program to fit T1(n, π*) inertial constants to the room-temperature contour. The determined values (cm-1), with 2σ confidence intervals, are A = 1.662 ± 0.003, B = 0.1485 ± 0.0006, C = 0.1363 ± 0.0004. Linewidth analysis of the jet-cooled spectrum yielded a value of 14 ± 2 ps for the lifetime of isolated acrolein molecules in the T1(n, π*), v = 0 state. We discuss the observed lifetime in the context of previous computational work on acrolein photochemistry. The spectroscopically derived inertial constants for the T1(n, π*) state were used to benchmark a variety of computational methods. One focus was on complete active space methods, such as complete active space self-consistent field (CASSCF) and second-order perturbation theory with a CASSCF reference function (CASPT2), which are applicable to excited states. We also examined the equation-of-motion coupled-cluster and time-dependent density function theory excited-state methods, and finally unrestricted ground-state techniques, including unrestricted density functional theory and unrestricted coupled-cluster theory with single and double and perturbative triple excitations. For each of the above methods, we or others [O. S. Bokareva et al., Int. J. Quantum Chem. 108, 2719 (2008)], 10.1002/qua.21803 used a triple zeta-quality basis set to optimize the T1(n, π*) geometry of acrolein. We find that the multiconfigurational methods provide the best agreement with fitted inertial

  20. Desorption of Hg(II) and Sb(V) on extracellular polymeric substances: effects of pH, EDTA, Ca(II) and temperature shocks. (United States)

    Zhang, Daoyong; Lee, Duu-Jong; Pan, Xiangliang


    Extracellular polymeric substances (EPS) existed ubiquitously in biological systems affect the mobility and availability of heavy metals in the environments. The adsorption-desorption behaviors of Hg(II) and Sb(V) on EPS were investigated. The sorption rates follow Sb(V) > Hg(II), and the desorption rates follow reverse order. Applications of ethylene diamine tetraacetic acid (EDTA), Ca(II) and pH shocks affect desorption rates and desorbed quantities of Hg(II) from EPS-Hg complex. Temperature shock minimally affects the desorption rate of Hg(II). Conversely, the EPS-Sb complex is stable subjected to EDTA, Ca(II), temperature or pH shocks. The excitation-emission matrix (EEM) fluorescence spectroscopy and fast-Fourier (FT-IR) analysis showed that Hg(II) and Sb(V) principally interacted with polysaccharides and protein-like compounds in the EPS, respectively. The EPS-Hg complex presents a time bomb that may release high levels of Hg(II) in short time period under environmental shocks.

  1. Triplet losses in dye lasers

    Energy Technology Data Exchange (ETDEWEB)

    Baczynski, A.; Kossakowski, A.; Marszalek, T. (Uniwersytet Mikolaja Kopernika, Torun (Poland). Instytut Fizyki)


    The expression for losses due to triplet states in dye laser considered as a six-level system is given. It is shown that triplet losses depend on pumping parameters and photon number. Depending on molecular and cavity parameters two differe types of behavior of dye lasers are expected. Physical conditions are discussed in which triplet losses as well as photon number undergo a jump at the threshold.

  2. Phasic Triplet Markov Chains. (United States)

    El Yazid Boudaren, Mohamed; Monfrini, Emmanuel; Pieczynski, Wojciech; Aïssani, Amar


    Hidden Markov chains have been shown to be inadequate for data modeling under some complex conditions. In this work, we address the problem of statistical modeling of phenomena involving two heterogeneous system states. Such phenomena may arise in biology or communications, among other fields. Namely, we consider that a sequence of meaningful words is to be searched within a whole observation that also contains arbitrary one-by-one symbols. Moreover, a word may be interrupted at some site to be carried on later. Applying plain hidden Markov chains to such data, while ignoring their specificity, yields unsatisfactory results. The Phasic triplet Markov chain, proposed in this paper, overcomes this difficulty by means of an auxiliary underlying process in accordance with the triplet Markov chains theory. Related Bayesian restoration techniques and parameters estimation procedures according to the new model are then described. Finally, to assess the performance of the proposed model against the conventional hidden Markov chain model, experiments are conducted on synthetic and real data.

  3. CaII Absorbers in the Sloan Digital Sky Survey: Element Abundances and Dust

    CERN Document Server

    Sardane, Gendith M; Rao, Sandhya M


    We present measurements of element abundance ratios and dust in CaII~absorbers identified in SDSS DR7+DR9. In an earlier paper we formed a statistical sample of 435 CaII absorbers and postulated that their statistical properties might be representative of at least two populations of absorbers. Here we show that if the absorbers are roughly divided into two subsamples with CaII rest equivalent widths larger and smaller than $W_0^{\\lambda 3934} = 0.7$ \\AA, they are then representative of two physically different populations. Comparisons of abundance ratios between the two CaII absorber populations indicate that the weaker $W_0^{\\lambda 3934}$ absorbers have properties consistent with halo-type gas, while the stronger absorbers have properties intermediate between halo- and disk-type gas. We also show that, on average, the dust extinction properties of the overall sample is consistent with a LMC or SMC dust law, and the stronger absorbers are nearly 6 times more reddened than their weaker counterparts. The absor...

  4. Formation of ultracold 7Li85Rb molecules in the lowest triplet electronic state by photoassociation and their detection by ionization spectroscopy (United States)

    Altaf, Adeel; Dutta, Sourav; Lorenz, John; Pérez-Ríos, Jesús; Chen, Yong P.; Elliott, D. S.


    We report the formation of ultracold 7Li85Rb molecules in the a3Σ+ electronic state by photoassociation (PA) and their detection via resonantly enhanced multiphoton ionization (REMPI). With our dual-species Li and Rb magneto-optical trap apparatus, we detect PA resonances with binding energies up to ˜62 cm-1 below the 7Li 2s 2S1/2 + 85Rb 5p 2P1/2 asymptote. In addition, we use REMPI spectroscopy to probe the a3Σ+ state and excited electronic 33Π and 43Σ+ states and identify a3Σ+ (v″ = 7-13), 33Π (vΠ' = 0-10), and 43Σ+ (vΣ' = 0-5) vibrational levels. Our line assignments agree well with ab initio calculations. These preliminary spectroscopic studies on previously unobserved electronic states are crucial to discovering transition pathways for transferring ultracold LiRb molecules created via PA to deeply bound rovibrational levels of the electronic ground state.

  5. Triplets pass their pressure test

    CERN Multimedia


    All the LHC inner triplets have now been repaired and are in position. The first ones have passed their pressure tests with flying colours. The repaired inner triplet at LHC Point 1, right side (1R). Ranko Ostojic (on the right), who headed the team responsible for repairing the triplets, shows the magnet to Robert Zimmer, President of the University of Chicago and of Fermi Research Alliance, who visited CERN on 20th August.Three cheers for the triplets! All the LHC inner triplets have now been repaired and are in position in the tunnel. Thanks to the mobilisation of a multidisciplinary team from CERN and Fermilab, assisted by the KEK Laboratory and the Lawrence Berkeley National Laboratory (LBNL), a solution has been found, tested, validated and applied. At the end of March this year, one of the inner triplets at Point 5 failed to withstand a pressure test. A fault was identified in the supports of two out of the three quadruple magne...

  6. Identification of a novel mutation in an Indian patient with CAII deficiency syndrome

    Directory of Open Access Journals (Sweden)

    Shivaprasad C


    Full Text Available Carbonic anhydrase II (CAII deficiency syndrome characterized by osteopetrosis (OP, renal tubular acidosis (RTA, and cerebral calcifications is caused by mutations in the carbonic anhydrase 2 (CA2 gene. Severity of this disorder varies depending on the nature of the mutation and its effect on the protein. We present here, the clinical and radiographic details along with, results of mutational analysis of the CA2 gene in an individual clinically diagnosed with renal tubular acidosis, osteopetrosis and mental retardation and his family members to establish genotype-phenotype correlation. A novel homozygous deletion mutation c.251delT was seen in the patient resulting in a frameshift and a premature stop codon at amino acid position 90 generating a truncated protein leading to a complete loss of function and a consequential deficiency of the enzyme making this a pathogenic mutation. Confirmation of clinical diagnosis by molecular methods is essential as the clinical features of the CAII deficiency syndrome are similar to other forms of OP but the treatment modalities are different. Genetic confirmation of the diagnosis at an early age leads to the timely institution of therapy improving the growth potential, reduces other complications like fractures, and aids in providing prenatal testing and genetic counseling to the parents planning a pregnancy.

  7. Resonance Raman and absorption spectroscopy of the lowest triplet state of 1,3,5-hexatriene and deuteriated derivatives at 183 K : molecular structure in the T1 state

    NARCIS (Netherlands)

    Langkilde, F.W.; Wilbrandt, R.; M?ller, S.; Brouwer, A.M.; Negri, F.; Orlandi, G.


    Time-resolved resonance Raman (RR) spectra of the lowest excited triplet state T1 of (E)-1,3,5-hexatriene, (E)-3-deuterio-1,3,5-hexatriene, and (E)-1,1-dideuterio-1,3,5-hexatriene are obtained at 183 K. The T1 potential energy surface (PES), determining energy minima, equilibrium geometries, frequen

  8. Topological Aspects of Triplet Superconductors

    Institute of Scientific and Technical Information of China (English)

    REN Ji-Rong; XU Dong-Hui; ZHANG Xin-Hui; LI Ran


    In this paper, using the φ-mapping theory, it is shown that two kinds of topological defects, i.e., the vortex lines and the monopoles exist in the helical configuration of magnetic field in triplet superconductors. And the inner topological structure of these defects is studied. Because the knot solitons in the triplet superconductors are characterized by the Hopf invariant, we also establish a relationship between the Hopf invariant and the linking number of knots family,and reveal the inner topological structure of the Hopf invariant.

  9. Dynamic Exchange During Triplet Transport in Nanocrystalline TIPS-Pentacene Films. (United States)

    Grieco, Christopher; Doucette, Grayson S; Pensack, Ryan D; Payne, Marcia M; Rimshaw, Adam; Scholes, Gregory D; Anthony, John E; Asbury, John B


    The multiplication of excitons in organic semiconductors via singlet fission offers the potential for photovoltaic cells that exceed the Shockley-Quiesser limit for single-junction devices. To fully utilize the potential of singlet fission sensitizers in devices, it is necessary to understand and control the diffusion of the resultant triplet excitons. In this work, a new processing method is reported to systematically tune the intermolecular order and crystalline structure in films of a model singlet fission chromophore, 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn), without the need for chemical modifications. A combination of transient absorption spectroscopy and quantitative materials characterization enabled a detailed examination of the distance- and time-dependence of triplet exciton diffusion following singlet fission in these nanocrystalline TIPS-Pn films. Triplet-triplet annihilation rate constants were found to be representative of the weighted average of crystalline and amorphous phases in TIPS-Pn films comprising a mixture of phases. Adopting a diffusion model used to describe triplet-triplet annihilation, the triplet diffusion lengths for nanocrystalline and amorphous films of TIPS-Pn were estimated to be ∼75 and ∼14 nm, respectively. Importantly, the presence of even a small fraction (materials may be essential to efficiently harvest multiplied triplets even when singlet fission occurs on ultrafast time scales.

  10. Interplay between singlet and triplet excited states in a conformationally locked donor–acceptor dyad

    KAUST Repository

    Filatov, Mikhail A.


    The synthesis and photophysical characterization of a palladium(II) porphyrin – anthracene dyad bridged via short and conformationally rigid bicyclo[2.2.2]octadiene spacer were achieved. A spectroscopic investigation of the prepared molecule in solution has been undertaken to study electronic energy transfer in excited singlet and triplet states between the anthracene and porphyrin units. By using steady-state and time-resolved photoluminescence spectroscopy it was shown that excitation of the singlet excited state of the anthracene leads to energy transfer to the lower-lying singlet state of porphyrin. Alternatively, excitation of the porphyrin followed by intersystem crossing to the triplet state leads to very fast energy transfer to the triplet state of anthracene. The rate of this energy transfer has been determined by transient absorption spectroscopy. Comparative studies of the dynamics of triplet excited states of the dyad and reference palladium octaethylporphyrin (PdOEP) have been performed.

  11. Triplet-triplet energy transfer and protection mechanisms against singlet oxygen in photosynthesis (United States)

    Kihara, Shigeharu

    In photosynthesis, (bacterio)chlorophylls ((B)Chl) play a crucial role in light harvesting and electron transport. (B)Chls, however, are known to be potentially dangerous due to the formation of the triplet excited state which forms the singlet oxygen (1O2*) when exposed to the sunlight. Singlet oxygen is highly reactive and all modern organisms incorporate special protective mechanisms to minimize the oxidative damage. One of the conventional photoprotective mechanisms used by photosynthetic organisms is by the nearby carotenoids quenching the excess energy and releasing it by heat. In this dissertation, two major aspects of this process are studied. First, based on experimental data and model calculations, the oxygen content in a functioning oxygenic photosynthetic oxygen cell was determined. These organisms perform water splitting and as a result significant amount of oxygen can be formed within the organism itself. It was found, that contrary to some published estimates, the excess oxygen concentration generated within an individual cell is extremely low -- 0.025 ... 0.25 microM, i.e. about 103-104 times lower than the oxygen concentration in air saturated water. Such low concentrations imply that the first oxygenic photosynthetic cells that evolved in oxygen-free atmosphere of the Earth ~2.8 billion years ago might have invented the water splitting machinery (photosystem II) without the need for special oxygen-protective mechanisms, and the latter mechanisms could have evolved in the next 500 million years during slow rise of oxygen in the atmosphere. This result also suggests that proteins within photosynthetic membranes are not exposed to significant O2 levels and thus can be studied in vitro under the usual O2 levels. Second, the fate of triplet excited states in the Fenna Matthew Olson (FMO) pigment-protein complex is studied by means of time-resolved nanosecond spectroscopy and exciton model simulations. For the first time, the properties of several

  12. Tough Decisions for Premature Triplets. (United States)

    Hurst, Ashley; Vergales, Brooke D; Paget-Brown, Alix; Mercurio, Mark; Lantos, John D


    When infants are born at the borderline of viability, doctors and parents have to make tough decisions about whether to institute intensive care or provide only palliative care. Often, these decisions are made in moments of profound emotional turmoil, and parents receive different information from different health professionals. Communication can become garbled. It may be difficult to tell when and whether the patient's clinical condition has changed enough so that certain choices that had once been permissible become impermissible. In this "Ethics Rounds," we present a case of triplets born at the borderline of viability. We sought comments from the triplets' parents, the doctors and ethicist who were caring for the infants, and a bioethicist/neonatologist from another hospital.

  13. A DFT-Based QSARs Study of Acetazolamide/Sulfanilamide Derivatives with Carbonic Anhydrase (CA-II Isozyme Inhibitory Activity

    Directory of Open Access Journals (Sweden)

    Oral Oltulu


    Full Text Available This study presents Quantitative Structure Activity Relationships (QSAR studyon a pool of 18 bio-active sulfonamide compounds which includes five acetazolamidederivatives, eight sulfanilamide derivatives and five clinically used sulfonamides moleculesas drugs namely acetazolamide, methazolamide, dichlorophenamide, ethoxolamide anddorzolamide. For all the compounds, initial geometry optimizations were carried out with amolecular mechanics (MM method using the MM force fields. The lowest energyconformations of the compounds obtained by the MM method were further optimized by theDensity Functional Theory (DFT method by employing Becke’s three-parameter hybridfunctional (B3LYP and 6-31G (d basis set. Molecular descriptors, dipole moment,electronegativity, total energy at 0 K, entropy at 298 K, HOMO and LUMO energiesobtained from DFT calculations provide valuable information and have a significant role inthe assessment of carbonic anhydrase (CA-II inhibitory activity of the compounds. By usingthe multiple linear regression technique several QSAR models have been drown up with thehelp these calculated descriptors and carbonic anhydrase (CA-II inhibitory data of themolecules. Among the obtained QSAR models presented in the study, statistically the mostsignificant one is a five parameters linear equation with the squared correlation coefficient R2 values of ca. 0.94 and the squared cross-validated correlation coefficient R2CV values of ca. 0.85. The results were discussed in the light of the main factors that influence theinhibitory activity of the carbonic anhydrase (CA-II isozyme.

  14. Ca(II) Binding Regulates and Dominates the Reactivity of a Transition-Metal-Ion-Dependent Diesterase from Mycobacterium tuberculosis. (United States)

    Pedroso, Marcelo M; Larrabee, James A; Ely, Fernanda; Gwee, Shuhui E; Mitić, Nataša; Ollis, David L; Gahan, Lawrence R; Schenk, Gerhard


    The diesterase Rv0805 from Mycobacterium tuberculosis is a dinuclear metallohydrolase that plays an important role in signal transduction by controlling the intracellular levels of cyclic nucleotides. As Rv0805 is essential for mycobacterial growth it is a promising new target for the development of chemotherapeutics to treat tuberculosis. The in vivo metal-ion composition of Rv0805 is subject to debate. Here, we demonstrate that the active site accommodates two divalent transition metal ions with binding affinities ranging from approximately 50 nm for Mn(II) to about 600 nm for Zn(II) . In contrast, the enzyme GpdQ from Enterobacter aerogenes, despite having a coordination sphere identical to that of Rv0805, binds only one metal ion in the absence of substrate, thus demonstrating the significance of the outer sphere to modulate metal-ion binding and enzymatic reactivity. Ca(II) also binds tightly to Rv0805 (Kd ≈40 nm), but kinetic, calorimetric, and spectroscopic data indicate that two Ca(II) ions bind at a site different from the dinuclear transition-metal-ion binding site. Ca(II) acts as an activator of the enzymatic activity but is able to promote the hydrolysis of substrates even in the absence of transition-metal ions, thus providing an effective strategy for the regulation of the enzymatic activity.

  15. Observational Searches for Chromospheric -Mode Oscillations from CaII H-Line Observations

    Indian Academy of Sciences (India)

    R. Kariyappa; L. Damé; K. M. Hiremath


    We have used a high spatial and temporal resolution of long time sequence of spectra in CaII H-line obtained at the Vacuum Tower Telescope (VTT) of the Sacramento Peak Observatory on a quiet region at the center of the solar disk over a large number of bright points and network elements to search for atmospheric (chromospheric) -mode oscillations. An important parameter of the H-line profile, intensity at H2V(IH2V), has been derived from a large number of line profiles. We derived the light curves of all the bright points and network elements. The light curves represent the main pulse with large intensity amplitude and followed by several follower pulses with lower intensity amplitudes. The light curves of these bright points would give an impression that one can as well draw curves towards and away from the highest peak (main pulse) showing an exponential growth and decay of the amplitudes. An exponential decaying function has been fitted for all the light curves of the bright points to determine the damping time of the modes that are more or less the same, and one value of the coefficient of exponent can represent reasonably well the decay for all the cases. The FFT analysis of temporal variation of both the bright points and the network elements indicates around 10-min periodicity. We speculate that this longer period of oscillation may be related to chromospheric -mode oscillations.

  16. Higher triplet state of fullerene C{sub 70} revealed by electron spin relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Uvarov, Mikhail N., E-mail: [Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, Institutskaya St. 3, 630090 Novosibirsk (Russian Federation); Behrends, Jan [Berlin Joint EPR Lab, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany); Kulik, Leonid V. [Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, Institutskaya St. 3, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova St. 2, Novosibirsk (Russian Federation)


    Spin-lattice relaxation times T{sub 1} of photoexcited triplets {sup 3}C{sub 70} in glassy decalin were obtained from electron spin echo inversion recovery dependences. In the range 30–100 K, the temperature dependence of T{sub 1} was fitted by the Arrhenius law with an activation energy of 172 cm{sup −1}. This indicates that the dominant relaxation process of {sup 3}C{sub 70} is described by an Orbach-Aminov mechanism involving the higher triplet state t{sub 2} which lies 172 cm{sup −1} above the lowest triplet state t{sub 1}. Chemical modification of C{sub 70} fullerene not only decreases the intrinsic triplet lifetime by about ten times but also increases T{sub 1} by several orders of magnitude. The reason for this is the presence of a low-lying excited triplet state in {sup 3}C{sub 70} and its absence in triplet C{sub 70} derivatives. The presence of the higher triplet state in C{sub 70} is in good agreement with the previous results from phosphorescence spectroscopy.

  17. Triplet Focusing for Recirculating Linear Muon Accelerators

    CERN Document Server

    Keil, Eberhard


    Focusing by symmetrical triplets is studied for the linear accelerator lattices in recirculating muon accelerators with several passes where the ratio of final to initial muon energy is about four. Triplet and FODO lattices are compared. At similar acceptance, triplet lattices have straight sections for the RF cavities that are about twice as long as in FODO lat-tices. For the same energy gain, the total lengths of the linear accelerators with triplet lattices are about the same as of those with FODO lattices.

  18. Design and construction of triplet atmospheric cold plasma jet for sterilization

    Directory of Open Access Journals (Sweden)

    F. Sohbatzadeh


    Full Text Available In this paper, construction of triplet atmospheric plasma jet using argon, air, oxygen and nitrogen gases is reported. Bactericidal effect of the plasma jet is also investigated. To that end, longitudinal geometric configuration for the electrodes was chosen because it would increase the jet length. Electrical characteristics, jet length dependencies on the applied voltage and gas flow rate were decided, experimentally. Relative concentrations of chemical reactive species such as ozone, atomic oxygen, NOx compounds and hydroxyl were measured using optical emission spectroscopy. It was seen that atomic oxygen and ozone concentrations with triplet plasma jet are more than the concentration of single plasma jet. Triplet plasma jet was also used for sterilization of solid and liquid surfaces to disinfect gram-negative and gram-positive Escherichia coli and Streptococcus pyogenes bacteria. The results verified the effectiveness of the triplet plasma jet for killing bacteria.

  19. Distribution of Triplet Separators in Bacterial Genomes

    Institute of Scientific and Technical Information of China (English)

    HU Rui; ZHENG Wei-Mou


    Distributions of triplet separator lengths for two bacterial complete genomes are analyzed. The theoretical distributions for the independent random sequence and the first-order Markov chain are derived and compared with the distributions of the bacterial genomes. A prominent double band structure, which does not exist in the theoretical distributions, is observed in the bacterial distributions for most triplets.``

  20. The near elimination of triplets in IVF. (United States)

    Gerris, Jan


    In Antwerp, single embryo transfers (SET) have increased, and this change in policy has seen the incidence of singletons rise from 70 to 90%, twins drop from 25 to 10%, and triplets drop from 1-2% to none at all. At a national and regional level, changes have been much more dramatic as a result of a change in the law in 2003 mandating SET. Data show a huge increase in the number of treatment cycles and a dramatic rise in SET. Rates of twins and triplets have dropped considerably. European data indicate wide differences in the incidence of triplets between countries, varying between 0% (e.g.Slovenia, Iceland, Lithuania) and 4.4% (Hungary), but almost nothing is known about the true incidence of fetal reduction. US data indicate some decrease in triplets during recent years, but certainly nowhere near elimination. These data suggest that in some countries, IVF triplets have almost been eliminated, but the problem is masked by significant fetal reductions. Where SET is not widely used, triplets are still frequent. A correlation appears to exist between the percentage of SET cycles and the incidence of triplets. It is suggested that the solution to almost totally eliminate triplets after IVF is single embryo transfer.

  1. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal


    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  2. Diphotons from an Electroweak Triplet-Singlet

    Energy Technology Data Exchange (ETDEWEB)

    Howe, Kiel [Fermilab; Knapen, Simon [UC, Berkeley; Robinson, Dean J. [UC, Berkeley


    The neutral component of a real pseudoscalar electroweak (EW) triplet can produce a diphoton excess at 750 GeV, if it is somewhat mixed with an EW singlet pseudoscalar. This triplet-singlet mixing allows for greater freedom in the diboson branching ratios than the singlet-only case, but it is still possible to probe the parameter space extensively with 300 fb$^{-1}$. The charged component of the triplet is pair-produced at the LHC, which results in a striking signal in the form of a pair of $W\\gamma$ resonances with an irreducible rate of 0.27 fb. Other signatures include multiboson final states from cascade decays of the triplet-singlet neutral states. A large class of composite models feature both EW singlet and triplet pseudo-Nambu Goldstone bosons in their spectrum, with the diboson couplings generated by axial anomalies.

  3. Definition and determination of the triplet-triplet energy transfer reaction coordinate

    Energy Technology Data Exchange (ETDEWEB)

    Zapata, Felipe; Marazzi, Marco; Castaño, Obis; Frutos, Luis Manuel, E-mail: [Departamento de Química Física, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid (Spain); Acuña, A. Ulises [Instituto de Química Física “Rocasolano”, C.S.I.C., Serrano 119, 28006 Madrid (Spain)


    A definition of the triplet-triplet energy transfer reaction coordinate within the very weak electronic coupling limit is proposed, and a novel theoretical formalism is developed for its quantitative determination in terms of internal coordinates The present formalism permits (i) the separation of donor and acceptor contributions to the reaction coordinate, (ii) the identification of the intrinsic role of donor and acceptor in the triplet energy transfer process, and (iii) the quantification of the effect of every internal coordinate on the transfer process. This formalism is general and can be applied to classical as well as to nonvertical triplet energy transfer processes. The utility of the novel formalism is demonstrated here by its application to the paradigm of nonvertical triplet-triplet energy transfer involving cis-stilbene as acceptor molecule. In this way the effect of each internal molecular coordinate in promoting the transfer rate, from triplet donors in the low and high-energy limit, could be analyzed in detail.

  4. Spectroscopy

    CERN Document Server

    Walker, S


    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  5. Synthesis, Structural Characterization, and Antitumor Activity of a Ca(II Coordination Polymer Based on 1,6-Naphthalenedisulfonate and 4,4′-Bipyridyl

    Directory of Open Access Journals (Sweden)

    Xishi Tai


    Full Text Available A novel Ca(II coordination polymer, [CaL(4,4′-bipyridyl(H2O4]n (L = 1,6-naphthalenedisulfonate, was synthesized by reaction of calcium perchlorate with 1,6-naphthalenedisulfonic acid disodium salt and 4,4′-bipyridyl in CH3CH2OH/H2O. It was characterized by elemental analysis, IR, molar conductivity and thermogravimetric analysis. X-ray crystallography reveals that the Ca(II coordination polymer belongs to the orthorhombic system, with space group P212121. The geometry of the Ca(II ion is a distorted CaNO6 pengonal bipyramid, arising from its coordination by four water molecules, one nitrogen atom of 4,4′-bipyridyl molecule, and two oxygen atoms from two L ligands. The complex molecules form a helical chain by self-assembly. The antitumor activity of 1,6-naphthalenedisulfonic acid disodium salt and the Ca(II coordination polymer against human hepatoma smmc-7721 cell line and human lung adenocarcinoma A549 cell line reveals that the Ca(II coordination polymer inhibits cell growth of human lung adenocarcinoma A549 cell line with IC50 value of 27 μg/mL, and is more resistive to human lung adenocarcinoma A549 cell line as compared to 1,6-naphthalenedisulfonic acid disodium salt.

  6. Cooper pairs spintronics in triplet spin valves. (United States)

    Romeo, F; Citro, R


    We study a spin valve with a triplet superconductor spacer intercalated between two ferromagnets with noncollinear magnetizations. We show that the magnetoresistance of the triplet spin valve depends on the relative orientations of the d vector, characterizing the superconducting order parameter, and the magnetization directions of the ferromagnetic layers. For devices characterized by a long superconductor, the effects of a polarized current sustained by Cooper pairs only are observed. In this regime, a supermagnetoresistance effect emerges, and the chiral symmetry of the order parameter of the superconducting spacer is easily recognized. Our findings open new perspectives in designing spintronics devices based on the cooperation of ferromagnetic and triplet correlations.

  7. Charge Carrier Generation Followed by Triplet State Formation, Annihilation, and Carrier Recreation in PBDTTT-C:PC 60 BM Photovoltaic Blends

    KAUST Repository

    Gehrig, Dominik W.


    Triplet state formation after photoexcitation of low-bandgap polymer:fullerene blends has recently been demonstrated, however, the precise mechanism and its impact on solar cell performance is still under debate. Here, we study exciton dissociation, charge carrier generation and triplet state formation in low-bandgap polymer PBDTTT-C:PC60BM bulk heterojunction photovoltaic blends by a combination of fs-µs broadband Vis-NIR transient absorption (TA) pump-probe spectroscopy and multivariate curve resolution (MCR) data analysis. We found sub-ps exciton dissociation and charge generation followed by sub-ns triplet state creation. The carrier dynamics and triplet state dynamics exhibited a very pronounced intensity dependence indicating non-geminate recombination of free carriers is the origin of triplet formation in these blends. Triplets were found to be the dominant state present on the nanosecond timescale. Surprisingly, the carrier population increased again on the ns-µs timescale. We attribute this to triplet-triplet annihilation and the formation of higher energy excited states that subsequently underwent charge transfer. This unique dip and recovery of the charge population is a clear indication that triplets are formed by non-geminate recombination, as such a kinetic is incompatible with a monomolecular triplet state formation process.

  8. Magnetic Field Effects on Triplet-Triplet Annihilation in Solutions: Modulation of Visible/NIR Luminescence. (United States)

    Mani, Tomoyasu; Vinogradov, Sergei A


    Photon upconversion based on sensitized triplet-triplet annihilation (TTA) presents interest for such areas as photovoltaics and imaging. Usually energy upconversion is observed as p-type delayed fluorescence from molecules whose triplet states are populated via energy transfer from a suitable triplet donor, followed by TTA. Magnetic field effects (MFE) on delayed fluorescence in molecular crystals are well known; however, there exist only a few examples of MFE on TTA in solutions, and all of them are limited to UV-emitting materials. Here we present MFE on TTA-mediated visible and near infrared (NIR) emission, sensitized by far-red absorbing metalloporphyrins in solutions at room temperature. In addition to visible delayed fluorescence from annihilator, we also observed NIR emission from the sensitizer, occurring as a result of triplet-triplet energy transfer back from annihilator, termed "delayed phosphorescence". This emission also exhibits MFE, but opposite in sign to the annihilator fluorescence.

  9. The stellar initial mass function in red-sequence galaxies: 1-micron spectroscopy of Coma Cluster galaxies with Subaru/FMOS

    CERN Document Server

    Smith, Russell J; Carter, David


    To investigate possible variations in the stellar initial mass function (IMF) in red-sequence galaxies, we have obtained infrared spectroscopy with Subaru/FMOS for a sample of 92 red-sequence galaxies in the Coma cluster. Velocity dispersions, ages and element abundances for these galaxies have been previously determined from optical data. By stacking the FMOS spectra in the rest frame, removing sky-subtraction residuals and other artefacts fixed in the observed frame, we derive composite spectra in the 9600-10500 Angstrom range for galaxies grouped according to their velocity dispersion or Mg/Fe ratio. We measure the Wing-Ford band of FeH and a new index centred on a CaI line at 10345 Angstrom; these features are strong in cool dwarf stars, and hence reflect the form of the IMF at low mass (<0.5M_sun) The CaI line, unlike the Wing-Ford band and other `classical' IMF indicators (NaI doublet, CaII triplet), is unaffected by the abundance of sodium. We compare the measured indices against predictions from sp...

  10. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  11. Triplet excitons in natural photosynthetic and artificial light harvesting systems: Measurement and modeling (United States)

    Hartzler, Daniel Allen

    Under full sunlight, unprotected (Bacterio)Chlorophyll ((B)Chl) molecules photodegrade in a matter of minutes. This is the result of the generation of highly reactive singlet oxygen (1O2) by energy transfer from the (B)Chl triplet state (3(B)Chl) to the oxygen ground state. Natural photosynthetic systems must protect themselves from 1O2, typically done by positioning carotenoids within a few angstroms of each (B)Chl molecule to quench 3(B)Chl states. Using phosphorescence spectroscopy and computational modeling, we investigated alternative, carotenoid independent, mechanisms which nature may employ to prevent 1O2 sensitization by lowering the energy of 3(B)Chl below that of 1O2. The two proposed triplet lowering mechanisms investigated were: triplet state lowering by strong pigment-pigment interactions (i.e. triplet exciton formation) and triplet state lowering by pigment-protein interactions. Possible natural examples employing these mechanisms are two structures found in green sulfur bacteria: the chlorosome (an antenna containing ~100000 coupled BChl c, d, or e molecules with unexpectedly high photostability) and the Fenna-Matthews-Olson (FMO) complex (an auxiliary antenna containing eight seemingly unprotected BChl a molecules). Measurements performed on linear aggregates of the dye perylene diimide (PDI) show that triplet exciton formation does reduce the triplet state energy. However, direct measurement of triplet state energies for the chlorosome and FMO complex proved experimentally difficult, thus an alternative approach was used to calculate these energies using empirical and excitonic models. Since the use of excitonic modeling requires knowledge of both the pigment site energies and the pigment-pigment interactions (i.e. couplings), work was performed to catalog the monomeric singlet and triplet state energies of all known natural (B)Chl pigments by direct measurement or computational modeling and to characterize the triplet-triplet (T-T) coupling in

  12. The large- and small-scale CaII K structure of the Milky Way from observations of Galactic and Magellanic sightlines

    CERN Document Server

    Smoker, J V; Fox, A J


    Aims: By utilising spectra of early-type stellar probes of known distances in the same region of the sky, the large and small-scale (pc) structure of the Galactic ISM can be investigated. This paper determines the variation in line strength of CaII at 3933.661 A, as a function of probe separation for a sample of stars, including many sightlines in the Magellanic Clouds. Methods: FLAMES-GIRAFFE data taken with the VLT towards early-type stars in 3 Galactic & 4 Magellanic open clusters in CaII are used to obtain the velocity, EW, column density and line width of IS Galactic Ca for a total of 657 stars, of which 443 are Magellanic sightlines. In each cluster there are 43-110 stars observed. Additionally, FEROS and UVES CaII & NaI spectra of 21 Galactic & 154 Magellanic early-type stars are presented and combined with data from the literature to study the Ca column density/parallax relationship. Results: For the four Magellanic clusters studied with FLAMES, the strength of the Galactic IS CaII K EW ov...

  13. Triplet excitons as sensitive spin probes for structure analysis of extended defects in microcrystalline silicon (United States)

    Meier, Christoph; Teutloff, Christian; Behrends, Jan; Bittl, Robert; Astakhov, Oleksandr; Lips, Klaus


    Electrically detected magnetic resonance (EDMR) spectroscopy is employed to study the influence of triplet excitons on the photocurrent in state-of-the-art microcrystalline silicon thin-film solar cells. These triplet excitons are used as sensitive spin probes for the investigation of their electronic and nuclear environment in this mixed-phase material. According to low-temperature EDMR results obtained from solar cells with different triplet excitons reside at extended defects in the crystallites of microcrystalline silicon that give rise to shallow states in the silicon band gap. The excitons possess a rather delocalized wave function, couple to electron spins in conduction band tail states nearby, and take part in a spin-dependent recombination process. Our study shows that extended defects such as grain boundaries or stacking faults in the crystalline part of the material act as charge carrier traps that can influence the material conductivity.

  14. VizieR Online Data Catalog: CaII spectroscopy of SMC red giants. IV. (Parisi+, 2016) (United States)

    Parisi, M. C.; Geisler, D.; Carraro, G.; Claria, J. J.; Villanova, S.; Gramajo, L. V.; Sarajedini, A.; Grocholski, A. J.


    This paper is a continuation of our previous work wherein we determined and analyzed the metallicity of 29 Small Magellanic Cloud (SMC) clusters (Parisi et al. 2009, Cat. J/AJ/138/517; Parisi et al. 2015, Cat. J/AJ/149/154) and that of a sample of ~350 red giant field stars (Parisi et al. 2010, Cat. J/AJ/139/1168) surrounding the 15 SMC star clusters studied in Parisi et al. 2009 (Cat. J/AJ/138/517). Here we add the ~400 red giants in 15 fields that surround the 14 star clusters studied in Parisi et al. 2015 (Cat. J/AJ/149/154) (in Parisi et al. 2015, Cat. J/AJ/149/154, we discard the cluster B113, but we can still use the surrounding field stars). We repeat here the identical procedures followed in Parisi et al. 2010 (Cat. J/AJ/139/1168). We refer the reader to Parisi et al. 2015 (Cat. J/AJ/149/154) for details regarding the selection of the cluster sample, the spectroscopic targets, and the observations. The list of the star clusters studied in Parisi et al. 2015 (Cat. J/AJ/149/154) can be seen in Table1 of that paper. Each cluster was centered on the master chip, while surrounding field stars were observed in both the master and secondary CCD. Pre-images in the V and I bands and the spectra of selected stars were obtained as part of programs 0.82B-0505 and 384.B-0687. The selection of spectroscopic targets was made on the corresponding (V, V-I) CMD by choosing stars located along the red giant branch. The spectroscopic observations were performed in service mode with the instrument FORS2 on the Very Large Telescope (VLT) in mask exchange unit mode (MXU), with the same instrumental setup as in Grocholski et al. 2006 (Cat. J/AJ/132/1630) and Parisi et al. 2009 (Cat. J/AJ/138/517). A very few stars have signal-to-noise ratio (S/N)~15pixel-1, but the remaining targets have S/N between ~20 and ~80pixel-1. Information about exposure times, size of the slits, seeing, and characteristics of the obtained spectra can be found in Section 3 of Parisi et al. 2015 (Cat. J/AJ/149/154). (2 data files).

  15. Ca(ii) and Ce(iii) homogeneous alginate hydrogels from the parent alginic acid precursor: a structural study. (United States)

    Sonego, Juan Manuel; Santagapita, Patricio R; Perullini, Mercedes; Jobbágy, Matías


    Alginate hydrogels are suitable for the encapsulation of biomolecules and microorganisms for the building of bioactive materials. Several alternatives to the conventional alginate formulation are being studied for a broad range of biotechnological applications; among them the crosslinking of alginate by lanthanide cations, Ln(iii), envisages expanded biomedical applications. The performance of these functional materials is highly related to the microstructure of the alginate matrix, which in turn is affected by the conditions of synthesis. In particular, when a diffusing gradient of the crosslinking cation is involved, microstructure inhomogeneities are expected at the macroscopic level. Here we discuss the subtle differences in the microstructure, as assessed by SAXS (Small Angle X-ray Scattering), established in the direction of the gradient of diffusion of Ca(ii) or Ce(iii).

  16. Triplet correlation functions in liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Dhabal, Debdas; Chakravarty, Charusita, E-mail: [Department of Chemistry, Indian Institute of Technology-Delhi, New Delhi 110016 (India); Singh, Murari [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Wikfeldt, Kjartan Thor [Science Institute, University of Iceland, 107 Reykjavik (Iceland)


    Triplet correlations have been shown to play a crucial role in the transformation of simple liquids to anomalous tetrahedral fluids [M. Singh, D. Dhabal, A. H. Nguyen, V. Molinero, and C. Chakravarty, Phys. Rev. Lett. 112, 147801 (2014)]. Here we examine triplet correlation functions for water, arguably the most important tetrahedral liquid, under ambient conditions, using configurational ensembles derived from molecular dynamics (MD) simulations and reverse Monte Carlo (RMC) datasets fitted to experimental scattering data. Four different RMC data sets with widely varying hydrogen-bond topologies fitted to neutron and x-ray scattering data are considered [K. T. Wikfeldt, M. Leetmaa, M. P. Ljungberg, A. Nilsson, and L. G. M. Pettersson, J. Phys. Chem. B 113, 6246 (2009)]. Molecular dynamics simulations are performed for two rigid-body effective pair potentials (SPC/E and TIP4P/2005) and the monatomic water (mW) model. Triplet correlation functions are compared with other structural measures for tetrahedrality, such as the O–O–O angular distribution function and the local tetrahedral order distributions. In contrast to the pair correlation functions, which are identical for all the RMC ensembles, the O–O–O triplet correlation function can discriminate between ensembles with different degrees of tetrahedral network formation with the maximally symmetric, tetrahedral SYM dataset displaying distinct signatures of tetrahedrality similar to those obtained from atomistic simulations of the SPC/E model. Triplet correlations from the RMC datasets conform closely to the Kirkwood superposition approximation, while those from MD simulations show deviations within the first two neighbour shells. The possibilities for experimental estimation of triplet correlations of water and other tetrahedral liquids are discussed.

  17. Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation

    Directory of Open Access Journals (Sweden)

    T. Stensitzki


    Full Text Available We combined femtosecond (fs VIS pump–IR probe spectroscopy with fs VIS pump–supercontinuum probe spectroscopy to characterize the photoreaction of the hexacoordinated Al(tpfc-Br8(py2 in a comprehensive way. Upon fs excitation at ∼400 nm in the Soret band, the excitation energy relaxes with a time constant of (250 ± 80 fs to the S2 and S1 electronic excited states. This is evident from the rise time of the stimulated emission signal in the visible spectral range. On the same time scale, narrowing of broad infrared signals in the C=C stretching region around 1500 cm−1 is observed. Energy redistribution processes are visible in the vibrational and electronic dynamics with time constants between ∼2 ps and ∼20 ps. Triplet formation is detected with a time constant of (95 ± 3 ps. This is tracked by the complete loss of stimulated emission. Electronic transition of the emerging triplet absorption band overlaps considerably with the singlet excited state absorption. In contrast, two well separated vibrational marker bands for triplet formation were identified at 1477 cm−1 and at 1508 cm−1. These marker bands allow a precise identification of triplet dynamics in corrole systems.

  18. Being Pregnant with Twins, Triplets and Other Multiples (United States)

    ... twins, triplets and other multiples Being pregnant with twins, triplets and other multiples E-mail to a ... embryos that grow into two or more babies. Twins are called identical when one fertilized egg splits ...

  19. Doublet-Triplet Splitting and Fat Branes

    CERN Document Server

    Maru, N


    We consider the doublet-triplet splitting problem in supersymmetric SU(5) grand unified theory in five dimensions where the fifth dimension is non-compact. We point out that an unnatural fine-tuning of parameters in order to obtain the light Higgs doublets is not required due to the exponential suppression of the overlap of the wave functions.

  20. Scalar triplet flavored leptogenesis: a systematic approach

    CERN Document Server

    Sierra, D Aristizabal; Hambye, Thomas


    Type-II seesaw is a simple scenario in which Majorana neutrino masses are generated by the exchange of a heavy scalar electroweak triplet. When endowed with additional heavy fields, such as right-handed neutrinos or extra triplets, it also provides a compelling framework for baryogenesis via leptogenesis. We derive in this context the full network of Boltzmann equations for studying leptogenesis in the flavored regime. To this end we determine the relations which hold among the chemical potentials of the various particle species in the thermal bath. This takes into account the SM Yukawa interactions of both leptons and quarks as well as sphaleron processes which, depending on the temperature, may be classified as faster or slower than the Hubble rate. We find that when leptogenesis is enabled by the presence of an extra triplet, lepton flavor effects allow the production of the $B-L$ asymmetry through lepton number conserving CP asymmetries. This scenario becomes dominant as soon as the triplets couple more t...

  1. Improving Fingerprint Verification Using Minutiae Triplets

    Directory of Open Access Journals (Sweden)

    Leopoldo Altamirano-Robles


    Full Text Available Improving fingerprint matching algorithms is an active and important research area in fingerprint recognition. Algorithms based on minutia triplets, an important matcher family, present some drawbacks that impact their accuracy, such as dependency to the order of minutiae in the feature, insensitivity to the reflection of minutiae triplets, and insensitivity to the directions of the minutiae relative to the sides of the triangle. To alleviate these drawbacks, we introduce in this paper a novel fingerprint matching algorithm, named M3gl. This algorithm contains three components: a new feature representation containing clockwise-arranged minutiae without a central minutia, a new similarity measure that shifts the triplets to find the best minutiae correspondence, and a global matching procedure that selects the alignment by maximizing the amount of global matching minutiae. To make M3gl faster, it includes some optimizations to discard non-matching minutia triplets without comparing the whole representation. In comparison with six verification algorithms, M3gl achieves the highest accuracy in the lowest matching time, using FVC2002 and FVC2004 databases.

  2. Carborane-Based Carbonic Anhydrase Inhibitors: Insight into CAII/CAIX Specificity from a High-Resolution Crystal Structure, Modeling, and Quantum Chemical Calculations

    Directory of Open Access Journals (Sweden)

    Pavel Mader


    Full Text Available Carborane-based compounds are promising lead structures for development of inhibitors of carbonic anhydrases (CAs. Here, we report structural and computational analysis applicable to structure-based design of carborane compounds with selectivity toward the cancer-specific CAIX isoenzyme. We determined the crystal structure of CAII in complex with 1-methylenesulfamide-1,2-dicarba-closo-dodecaborane at 1.0 Å resolution and used this structure to model the 1-methylenesulfamide-1,2-dicarba-closo-dodecaborane interactions with CAIX. A virtual glycine scan revealed the contributions of individual residues to the energy of binding of 1-methylenesulfamide-1,2-dicarba-closo-dodecaborane to CAII and CAIX, respectively.

  3. Synthesis and Exciton Dynamics of Triplet Sensitized Conjugated Polymers

    KAUST Repository

    Andernach, Rolf


    We report the synthesis of a novel polythiophene-based host-guest copolymer incorporating a Pt-porphyrin complex (TTP-Pt) into the backbone for efficient singlet to triplet polymer exciton sensitization. We elucidated the exciton dynamics in thin films of the material by means of Transient Absorption Spectrosopcy (TAS) on multiple timescales and investigated the mechanism of triplet exciton formation. During sensitization, single exciton diffusion is followed by exciton transfer from the polymer backbone to the complex where it undergoes intersystem crossing to the triplet state of the complex. We directly monitored the triplet exciton back transfer from the Pt-porphyrin to the polymer and find that 60% of the complex triplet excitons are transferred with a time constant of 1087 ps. We propose an equilibrium between polymer and porphyrin triplet states as a result of the low triplet diffusion length in the polymer backbone and hence an increased local triplet population resulting in increased triplet-triplet annihilation. This novel system has significant implications for the design of novel materials for triplet sensitized solar cells and up-conversion layers.

  4. The NIR Ca II triplet at low metallicity : Searching for extremely low-metallicity stars in classical dwarf galaxies

    NARCIS (Netherlands)

    Starkenburg, E.; Hill, V.; Tolstoy, E.; Gonzalez Hernandez, J.I.; Irwin, M.; Helmi, A.; Battaglia, G.; Jablonka, P.; Tafelmeyer, M.; Shetrone, M.; Venn, K.; de Boer, T.


    The NIR Ca II triplet absorption lines have proven to be an important tool for quantitative spectroscopy of individual red giant branch stars in the Local Group, providing a better understanding of metallicities of stars in the Milky Way and dwarf galaxies and thereby an opportunity to constrain the

  5. Relationship between breakthrough curve and adsorption isotherm of Ca(II) imprinted chitosan microspheres for metal adsorption

    Institute of Scientific and Technical Information of China (English)

    Yangcheng Lu; Jing He; Longwen Wu; Guangsheng Luo


    In this work, an equilibrium-dispersion model was successfully established to describe the breakthrough performance of Ca(II) imprinted chitosan (Ca(II)-CS) microspheres packed column for metal adsorption, and the assumptions of Langmuir isotherms and axial dispersion controlled mass transfer process were confirmed. The axial dispersion coefficient in Ca(II)-CS microspheres packed column was found to be almost proportional to the linear velocity and fit for prediction through single breakthrough test. Sensitivity analysis for breakthrough curve indicated the axial dispersion coefficient as well as Langmuir coefficient was sensitive variable for deep removal requirement. The retrieval of the adsorption isotherms of Ca(II)-CS microspheres from breakthrough curve was fulfilled by model ing calibration. A strategy based on the correlation between adsorption isotherms and breakthrough performance was further proposed to simplify the column adsorption design using absorbents with smal/uniform size and fast adsorption kinetics like Ca(II)-CS microspheres to cut down the gap between lab and industry.

  6. Radiative Neutrino Mass with Scotogenic Scalar Triplet

    CERN Document Server

    Brdar, Vedran; Radovcic, Branimir


    We present radiative one-loop neutrino mass model with hypercharge zero scalar triplet in conjunction with another charged singlet scalar and an additional vectorlike lepton doublet. We study three variants of this mass model: the first one without additional beyond-SM symmetry, the second with imposed DM-stabilizing discrete Z_2 symmetry, and the third in which this Z_2 symmetry is promoted to the gauge symmetry U(1)_D. The two latter cases are scotogenic, with a neutral component of the scalar triplet as a dark matter candidate. In first scotogenic model the Z_2-odd dark matter candidate is at the multi-TeV mass scale, so that all new degrees of freedom are beyond the direct reach of the LHC. In second scotogenic setup, with broken U(1)_D symmetry the model may have LHC signatures or be relevant to astrophysical observations, depending on the scale of U(1)_D breaking.

  7. Fermiophobia in a Higgs Triplet Model

    CERN Document Server

    Akeroyd, A G; Rivera, Maximiliano A; Romero, Diego


    A Fermiophobic Higgs boson can arise in models with an extended Higgs sector, such as models with scalars in an isospin triplet representation. In a specific model with a scalar triplet and spontaneous violation of lepton number induced by a scalar singlet field, we show that fermiophobia is not a fine-tuned situation, unlike in Two Higgs Doublet Models. We study distinctive signals of fermiophobia which can be probed at the LHC. For the case of a small Higgs mass a characteristic signal would be a moderate B(H ->\\gamma\\gamma) accompanied by a large B(H -> JJ) (where J is a Majoron), the latter being an invisible decay. For the case of a large Higgs mass there is the possibility of dominant H -> ZZ, WW and suppressed H -> JJ decay modes. In this situation, B(H -> ZZ) is larger than B(H -> WW), which differs from the SM prediction.

  8. Nickelocene: A universal quencher of organic triplets (United States)

    Rajadurai, S.; Bhattacharyya, K.; Das, P. K.


    Organic triplets, with energies in the range 0.9-3.2 eV, are quenched by nickelocene with rate constants in the limit of diffusion control ((1.3-11) × 109 M-1s-1 in benzene). The efficient quenching, explainable in terms of a combination of energy and electron transfer, suggests the existence of a low-lying spin-forbidden transition (< 0.9 eV) in nickelocene.

  9. Structural basis for triplet repeat disorders

    DEFF Research Database (Denmark)

    Baldi, Pierre; Brunak, Søren; Chauvin, Yves


    Motivation: Over a dozen major degenerative disorders, including myotonic distrophy, Huntington's disease and fragile X syndrome result from unstable expansions of particular trinucleotides. Remarkably, only some of all the possible triplets, namely CAG/CTG, CGG/CCG and GAA/TTC, have been associa......, which we predict to have very high flexibility, may play a role in the pathogenesis of the neurodegenerative disorder multiple system atrophy (MSA)....

  10. Twin and Triplet Drugs in Opioid Research (United States)

    Fujii, Hideaki

    Twin and triplet drugs are defined as compounds that contain respectively two and three pharmacophore components exerting pharmacological effects in a molecule. The twin drug bearing the same pharmacophores is a "symmetrical twin drug", whereas that possessing different pharmacophores is a "nonsymmetrical twin drug." In general, the symmetrical twin drug is expected to produce more potent and/or selective pharmacological effects, whereas the nonsymmetrical twin drug is anticipated to show both pharmacological activities stemming from the individual pharmacophores (dual action). On the other hand, nonsymmetrical triplet drugs, which have two of the same pharmacophores and one different moiety, are expected to elicit both increased pharmacological action and dual action. The two identical portions could bind the same receptor sites simultaneously while the third portion could bind a different receptor site or enzyme. This review will mainly focus on the twin and triplet drugs with an evaluation of their in vivo pharmacological effects, and will also include a description of their pharmacology and synthesis.

  11. Integrals over the triplet distribution function without the triplet distribution function (United States)

    Lado, F.

    While the triplet distribution function of disordered systems appears in a wide variety of problems in statistical mechanics, it does so always under an integral sign. In this paper, we propose a new method of evaluating such integrals that involves only pair functions throughout and avoids altogether the need for any explicit representation of the little-known triplet function. The procedure is based on an extension of integral equation theory of classical fluids. Numerical illustrations of the method are given for integrals that arise in the calculation of moments of a local field distribution.

  12. Dye-Sensitized Solar Cell with Integrated Triplet-Triplet Annihilation Upconversion System. (United States)

    Nattestad, Andrew; Cheng, Yuen Yap; MacQueen, Rowan W; Schulze, Tim F; Thompson, Fletcher W; Mozer, Attila J; Fückel, Burkhard; Khoury, Tony; Crossley, Maxwell J; Lips, Klaus; Wallace, Gordon G; Schmidt, Timothy W


    Photon upconversion (UC) by triplet-triplet annihilation (TTA-UC) is employed in order to enhance the response of solar cells to sub-bandgap light. Here, we present the first report of an integrated photovoltaic device, combining a dye-sensitized solar cell (DSC) and TTA-UC system. The integrated device displays enhanced current under sub-bandgap illumination, resulting in a figure of merit (FoM) under low concentration (3 suns), which is competitive with the best values recorded to date for nonintegrated systems. Thus, we demonstrate both the compatibility of DSC and TTA-UC and a viable method for device integration.

  13. Odd triplet superconductivity in superconductor ferromagnet structures: a survey

    Energy Technology Data Exchange (ETDEWEB)

    Bergeret, F.S. [Universidad Autonoma de Madrid, Departamento de Fisica Teorica de la Materia Condensada C-V, Madrid (Spain); Volkov, A.F. [Ruhr-Universitaet Bochum, Theoretische Physik III, Bochum (Germany); Russian Academy of Sciences, Institute for Radioengineering and Electronics, Moscow (Russian Federation); Efetov, K.B. [Ruhr-Universitaet Bochum, Theoretische Physik III, Bochum (Germany); L.D. Landau Institute for Theoretical Physics RAS, Moscow (Russian Federation)


    We review the main features of odd triplet superconductivity in superconductor-ferromagnet (S/F) structures. We discuss the different types of superconducting condensate that can be experimentally observed and pay special attention to the triplet component induced in a ferromagnet which is in contact with a superconductor. The triplet component is an even function of the momentum and an odd function of the frequency and leads to novel phenomena. (orig.)

  14. Half-metallic superconducting triplet spin valve (United States)

    Halterman, Klaus; Alidoust, Mohammad


    We theoretically study a finite-size S F1N F2 spin valve, where a normal metal (N ) insert separates a thin standard ferromagnet (F1) and a thick half-metallic ferromagnet (F2). For sufficiently thin superconductor (S ) widths close to the coherence length ξ0, we find that changes to the relative magnetization orientations in the ferromagnets can result in substantial variations in the transition temperature Tc, consistent with experimental results [Singh et al., Phys. Rev. X 5, 021019 (2015), 10.1103/PhysRevX.5.021019]. Our results demonstrate that, in good agreement with the experiment, the variations are largest in the case where F2 is in a half-metallic phase and thus supports only one spin direction. To pinpoint the origins of this strong spin-valve effect, both the equal-spin f1 and opposite-spin f0 triplet correlations are calculated using a self-consistent microscopic technique. We find that when the magnetization in F1 is tilted slightly out of plane, the f1 component can be the dominant triplet component in the superconductor. The coupling between the two ferromagnets is discussed in terms of the underlying spin currents present in the system. We go further and show that the zero-energy peaks of the local density of states probed on the S side of the valve can be another signature of the presence of superconducting triplet correlations. Our findings reveal that for sufficiently thin S layers, the zero-energy peak at the S side can be larger than its counterpart in the F2 side.

  15. Singlet-triplet annihilation limits exciton yield in poly(3-hexylthiophene)

    CERN Document Server

    Steiner, Florian; Lupton, John M


    Control of chain length and morphology in combination with single-molecule spectroscopy techniques provide a comprehensive photophysical picture of excited-state losses in the prototypical conjugated polymer poly(3-hexylthiophene) (P3HT). A universal self-quenching mechanism is revealed, based on singlet-triplet exciton annihilation, which accounts for the dramatic loss in fluorescence quantum yield of a single P3HT chain between its solution (unfolded) and bulk-like (folded) state. Triplet excitons fundamentally limit the fluorescence of organic photovoltaic materials, which impacts on the conversion of singlet excitons to separated charge carriers, decreasing the efficiency of energy harvesting at high excitation densities. Interexcitonic interactions are so effective that a single P3HT chain of >100 kDa weight behaves like a two-level system, exhibiting perfect photon-antibunching.

  16. Powering the High-Luminosity Triplets

    CERN Document Server

    Ballarino, A


    The powering of the magnets in the LHC High-Luminosity Triplets requires production and transfer of more than 150 kA of DC current. High precision power converters will be adopted, and novel High Temperature Superconducting (HTS) current leads and MgB2 based transfer lines will provide the electrical link between the power converters and the magnets. This chapter gives an overview of the systems conceived in the framework of the LHC High-Luminosity upgrade for feeding the superconducting magnet circuits. The focus is on requirements, challenges and novel developments.

  17. Scalar triplet on a domain wall: an exact solution

    CERN Document Server

    Gani, Vakhid A; Radomskiy, Roman V


    We study a model with a real scalar Higgs field and a scalar triplet field that allows existence of a topological defect -- a domain wall. The wall breaks the global $O(3)$ symmetry of the model, which gives rise to non-Abelian orientational degrees of freedom. We found an exact analytic solution that describes a domain wall with a localized configuration of the triplet field on it. This solution enables one to calculate contributions to the action from the orientational and translational degrees of freedom of the triplet field. We also study the linear stability of the domain wall with the triplet field switched off.

  18. Radiative neutrino mass with scotogenic scalar triplet

    Energy Technology Data Exchange (ETDEWEB)

    Brdar, Vedran; Picek, Ivica; Radovčić, Branimir


    We present a radiative one-loop neutrino mass model with hypercharge zero scalar triplet in conjunction with another charged singlet scalar and an additional vectorlike lepton doublet. We study three variants of this mass model: the first one without additional beyond-SM symmetry, the second with imposed DM-stabilizing discrete Z{sub 2} symmetry, and the third in which this Z{sub 2} symmetry is promoted to the gauge symmetry U(1){sub D}. The two latter cases are scotogenic, with a neutral component of the scalar triplet as a dark matter candidate. In first scotogenic model the Z{sub 2}-odd dark matter candidate is at the multi-TeV mass scale, so that all new degrees of freedom are beyond the direct reach of the LHC. In second scotogenic setup, with broken U(1){sub D} symmetry the model may have LHC signatures or be relevant to astrophysical observations, depending on the scale of U(1){sub D} breaking.

  19. The superconducting spin valve and triplet superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Garifullin, I.A., E-mail: [Zavoisky Physical-Technical Institute, Kazan Scientific Center of Russian Academy of Sciences, 420029 Kazan (Russian Federation); Leksin, P.V.; Garif' yanov, N.N.; Kamashev, A.A. [Zavoisky Physical-Technical Institute, Kazan Scientific Center of Russian Academy of Sciences, 420029 Kazan (Russian Federation); Fominov, Ya.V. [L. D. Landau Institute for Theoretical Physics RAS, 119334 Moscow (Russian Federation); Moscow Institute of Physics and Technology, 141700 Dolgoprudny (Russian Federation); Schumann, J.; Krupskaya, Y.; Kataev, V.; Schmidt, O.G. [Leibniz Institute for Solid State and Materials Research IFW Dresden, D-01171 Dresden (Germany); Büchner, B. [Leibniz Institute for Solid State and Materials Research IFW Dresden, D-01171 Dresden (Germany); Institut für Festkörperphysik, Technische Universität Dresden, D-01062 Dresden (Germany)


    A review of our recent results on the spin valve effect is presented. We have used a theoretically proposed spin switch design F1/F2/S comprising a ferromagnetic bilayer (F1/F2) as a ferromagnetic component, and an ordinary superconductor (S) as the second interface component. Based on it we have prepared and studied in detail a set of multilayers CoO{sub x}/Fe1/Cu/Fe2/S (S=In or Pb). In these heterostructures we have realized for the first time a full spin switch effect for the superconducting current, have observed its sign-changing oscillating behavior as a function of the Fe2-layer thickness and finally have obtained direct evidence for the long-range triplet superconductivity arising due to noncollinearity of the magnetizations of the Fe1 and Fe2 layers. - Highlights: • We studied a spin switch design F1/F2/S. • We prepared a set of multilayers CoOx/Fe1/Cu/Fe2/S (S=In or Pb). • The full spin switch effect for the superconducting current was realized. • We observed its oscillating behavior as a function of the Fe2-layer thickness. • We obtained direct evidence for the long-range triplet superconductivity.

  20. Higgs Triplet Model with Classically Conformal Invariance

    CERN Document Server

    Okada, Hiroshi; Yagyu, Kei


    We discuss an extension of the minimal Higgs triplet model with a classically conformal invariance and with a gauged $U(1)_{B-L}$ symmetry. In our scenario, tiny masses of neutrinos are generated by a hybrid contribution from the type-I and type-II seesaw mechanisms. The shape of the Higgs potential at low energies is determined by solving one-loop renormalization group equations for all the scalar quartic couplings with a set of initial values of parameters at the Planck scale. We find a successful set of the parameters in which the $U(1)_{B-L}$ symmetry is radiatively broken via the Coleman-Weinberg mechanism at the ${\\cal O}$(10) TeV scale, and the electroweak symmetry breaking is also triggered by the $U(1)_{B-L}$ breaking. Under this configuration, we can predict various low energy observables such as the mass spectrum of extra Higgs bosons, and the mixing angles. Furthermore, using these predicted mass parameters, we obtain upper limits on Yukawa couplings among an isospin triplet Higgs field and lepton...

  1. The neonatal outcome in twin versus triplet and quadruplet pregnancies

    Directory of Open Access Journals (Sweden)

    Fatemeh Nasseri


    Full Text Available

    • BACKGROUND: To assess the risk of neonatal mortality and morbidity in twin, triplet and quadruplet pregnancies.
    • METHODS: In a retrospective study, the neonatal outcome of all twin, triplet and quadruplet gestations delivered from October 2001 to September 2006 was reviewed. The neonatal outcome of triples and quadruplets was compared with a matched group of twins for gestational age.
    • RESULTS: During a 5-year period, 511 sets of twin pregnancies, 42 sets of triplet and 5 sets of quadruplet pregnancies were studied. The mean of gestational age for twins, triplets and quadruplets were 33.92 ± 3.5 weeks, 30.92 ± 3.8 weeks and 31.60 ± 2.0 weeks, respectively, (P = 0.0001. Triplets and quadruplets weighed less than twins, (P = 0.0001. Neonatal mortality was 13.5% for twins, 26.8% for triplets and 30% for quadruplets. In vitro fertilization, use of ovulation induction agents, and cesarean delivery in the women with triplet and quadruplet were significantly higher than in those with twin pregnancies, (P = 0.0001. The mean age of mothers with triplets and quadruplets was significantly higher than with twins (P = 0.026. There was not a significant difference in respiratory and non-respiratory short outcomes between triplets, quadruplets and twins when matched for gestational age. Apgar score at 1 and 5 minutes was significantly lower in triplets and quadruplets than twins. There was no influence of birth order on neonatal mortality of triplet pregnancy. Neonatal mortality of triplet births was significantly decreased over the 5 years of the study period.
    • CONCLUSIONS: Triplets and quadruplets have a similar neonatal outcome as twins when matched for gestational age. There is no influence of birth on the neonatal mortality of triplet pregnancy. It appears that outcome is mainly dependent on gestational age.
    • KEYWORDS: Neonatal

    • Maternal and perinatal complications in triplet compared with twin pregnancy

      NARCIS (Netherlands)

      J.G. Santema (Job); P. Bourdrez (Petra); H.C.S. Wallenburg (Henk)


      textabstractObjective: To compare maternal and perinatal complications in triplet and twin pregnancies. Study design: Case-controlled study in the setting of a University Hospital. Each pregnancy of a consecutive series of 40 triplet pregnancies of 20 weeks or more was matched for parity and materna

    • Time-Varying Triplet State Lifetimes of Single Molecules

      NARCIS (Netherlands)

      Veerman, J.A.; Garcia-Parajo, M.F.; Kuipers, L.; Hulst, van N.F.


      It is found that triplet state lifetimes and intersystem crossing yields of individual molecules embedded in a polymer host at room temperature are not constant in time. The range over which the triplet lifetime of a single molecule varies during long observation times shows a strong similarity with

    • Reversible Triplet Energy Transfer between Neo- Alloocimene and Anthracene

      DEFF Research Database (Denmark)

      Gorman, A. A.; Hamblett, I.; Jensen, Niels-Henrik


      The rate constants for triplet energy transfer between neo-alloocimene and anthracene have been redetermined by a combination of pulsed laser photolysi......The rate constants for triplet energy transfer between neo-alloocimene and anthracene have been redetermined by a combination of pulsed laser photolysi...

    • Three-Triplet Model with Double SU(3) Symmetry (United States)

      Han, M. Y.; Nambu, Y.


      With a view to avoiding some of the kinematical and dynamical difficulties involved in the single triplet quark model, a model for the low lying baryons and mesons based on three triplets with integral charges is proposed, somewhat similar to the two-triplet model introduced earlier by one of us (Y. N.). It is shown that in a U(3) scheme of triplets with integral charges, one is naturally led to three triplets located symmetrically about the origin of I{sub 3} - Y diagram under the constraint that Nishijima-Gell-Mann relation remains intact. A double SU(3) symmetry scheme is proposed in which the large mass splittings between different representations are ascribed to one of the SU(3), while the other SU(3) is the usual one for the mass splittings within a representation of the first SU(3).

    • Measurement of Nanomolar Dissociation Constants by Titration Calorimetry and Thermal Shift Assay – Radicicol Binding to Hsp90 and Ethoxzolamide Binding to CAII

      Directory of Open Access Journals (Sweden)

      Vilma Michailovienė


      Full Text Available The analysis of tight protein-ligand binding reactions by isothermal titration calorimetry (ITC and thermal shift assay (TSA is presented. The binding of radicicol to the N-terminal domain of human heat shock protein 90 (Hsp90aN and the binding of ethoxzolamide to human carbonic anhydrase (hCAII were too strong to be measured accurately by direct ITC titration and therefore were measured by displacement ITC and by observing the temperature-denaturation transitions of ligand-free and ligand-bound protein. Stabilization of both proteins by their ligands was profound, increasing the melting temperature by more than 10 ºC, depending on ligand concentration. Analysis of the melting temperature dependence on the protein and ligand concentrations yielded dissociation constants equal to 1 nM and 2 nM for Hsp90aN-radicicol and hCAII-ethoxzolamide, respectively. The ligand-free and ligand-bound protein fractions melt separately, and two melting transitions are observed. This phenomenon is especially pronounced when the ligand concentration is equal to about half the protein concentration. The analysis compares ITC and TSA data, accounts for two transitions and yields the ligand binding constant and the parameters of protein stability, including the Gibbs free energy and the enthalpy of unfolding.

    • Spectroscopic characterization of the competitive binding of Eu(III), Ca(II), and Cu(II) to a sedimentary originated humic acid

      Energy Technology Data Exchange (ETDEWEB)

      Marang, L.; Reiller, P.E. [CEA Saclay, Nucl Energy Div, DPC SECR, Lab Speciat Radionucleides and Mol, 91 - Gif sur Yvette (France); Marang, L.; Benedetti, M.F. [Univ Paris 07, Lab Geochim Eaux, IPGP UMR CNRS 7154, F-75205 Paris 13 (France); Eidner, S.; Kumke, M.U. [Univ Potsdam, Inst Chem, D-14476 Potsdam (Germany)


      The competition between REE, alkaline earth and d-transition metals for organic matter binding sites is still an open field of research; particularly, the mechanisms governing these phenomena need to be characterized in more detail. In this study, we examine spectroscopically the mechanisms of competitive binding of Eu(III)/Cu(II) and Eu(III)/Ca(II) pair to Gorleben humic acid (HA), as previously proposed in the framework of the NICA-Donnan model. The evolution of time-resolved laser induced luminescence spectra of humic-complexed Eu(Ill) showed two strikingly different environments for a comparable bound proportion for Cu(II) and Ca(II). Cu(II) seems to compete more effectively with Eu(III) inducing its release into the Donnan phase, and into the bulk solution as free Eu{sup 3+}. This is evidenced both by the shapes of the spectra and by the decrease in the luminescence decay times. In contrast with that, Ca(II) induces a modification of the HA structure, which enhances the luminescence of humic-bound Eu(III), and causes a minor modification of the chemical environment of the complexed rare earth ion. (authors)

    • Synthesis, spectroscopic, thermal and anticancer studies of metal-antibiotic chelations: Ca(II), Fe(III), Pd(II) and Au(III) chloramphenicol complexes (United States)

      Al-Khodir, Fatima A. I.; Refat, Moamen S.


      Four Ca(II), Fe(III), Pd(II) and Au(III) complexes of chloramphenicol drug have been synthesized and well characterized using elemental analyses, (infrared, electronic, and 1H-NMR) spectra, magnetic susceptibility measurement, and thermal analyses. Infrared spectral data show that the chloramphenicol drug coordinated to Ca(II), Pd(II) and Au(III) metal ions through two hydroxyl groups with 1:1 or 1:2 M ratios, but Fe(III) ions chelated towards chloramphenicol drug via the oxygen and nitrogen atoms of amide group with 1:2 ratio based on presence of keto↔enol form. The X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques were used to identify the nano-size particles of both iron(III) and gold(III) chloramphenicol complexes. The antimicrobial assessments of the chloramphenicol complexes were scanned and collected the results against of some kind of bacteria and fungi. The cytotoxic activity of the gold(III) complex was tested against the human colon carcinoma (HCT-116) and human hepatocellular carcinoma (HepG-2) tumor cell lines.

    • Triplet-triplet annihilation photon-upconversion: towards solar energy applications. (United States)

      Gray, Victor; Dzebo, Damir; Abrahamsson, Maria; Albinsson, Bo; Moth-Poulsen, Kasper


      Solar power production and solar energy storage are important research areas for development of technologies that can facilitate a transition to a future society independent of fossil fuel based energy sources. Devices for direct conversion of solar photons suffer from poor efficiencies due to spectrum losses, which are caused by energy mismatch between the optical absorption of the devices and the broadband irradiation provided by the sun. In this context, photon-upconversion technologies are becoming increasingly interesting since they might offer an efficient way of converting low energy solar energy photons into higher energy photons, ideal for solar power production and solar energy storage. This perspective discusses recent progress in triplet-triplet annihilation (TTA) photon-upconversion systems and devices for solar energy applications. Furthermore, challenges with evaluation of the efficiency of TTA-photon-upconversion systems are discussed and a general approach for evaluation and comparison of existing systems is suggested.

    • Magnetic chains on a triplet superconductor. (United States)

      Sacramento, P D


      The topological state of a two-dimensional triplet superconductor may be changed by an appropriate addition of magnetic impurities. A ferromagnetic magnetic chain at the surface of a superconductor with spin-orbit coupling may eliminate the edge states of a finite system giving rise to localized zero modes at the edges of the chain. The coexistence/competition between the two types of zero modes is considered. The reduction of the system to an effective 1d system gives partial information on the topological properties but the study of the two sets of zero modes requires a two-dimensional treatment. Increasing the impurity density from a magnetic chain to magnetic islands leads to a finite Chern number. At half-filling small concentrations are enough to induce chiral modes.

    • Spontaneous Heterotopic Triplet Pregnancy With Tubal Rupture

      Directory of Open Access Journals (Sweden)

      Lima Arsala MBBS, BBMedSci


      Full Text Available The recent increase in heterotopic pregnancies has been largely attributed to the increased use of assisted reproduction technologies. We report the rare case of a multiparous woman with a spontaneous conception resulting in a triplet heterotopic pregnancy: a twin intrauterine pregnancy and a single right tubal ectopic pregnancy. Heterotopic pregnancy is a rare and potentially life-threatening condition in which simultaneous gestations occur at 2 or more implantation sites. It is infrequent in natural conception cycles, occurring in 1:30 000 pregnancies. However, the prevalence is rising with the increased use of assisted reproduction techniques to that of 1:100 to 1:500 in these patient subgroups, highlighting the need to incorporate it into a clinician’s diagnostic algorithm.

    • Bright Solid State Source of Photon Triplets

      CERN Document Server

      Khoshnegar, Milad; Predojević, Ana; Dalacu, Dan; Prilmüller, Maximilian; Lapointe, Jean; Wu, Xiaohua; Tamarat, Philippe; Lounis, Brahim; Poole, Philip; Weihs, Gregor; Majedi, Hamed


      Producing advanced quantum states of light is a priority in quantum information technologies. While remarkable progress has been made on single photons and photon pairs, multipartite correlated photon states are usually produced in purely optical systems by post-selection or cascading, with extremely low efficiency and exponentially poor scaling. Multipartite states enable improved tests of the foundations of quantum mechanics as well as implementations of complex quantum optical networks and protocols. It would be favorable to directly generate these states using solid state systems, for better scaling, simpler handling, and the promise of reversible transfer of quantum information between stationary and flying qubits. Here we use the ground states of two optically active coupled quantum dots to directly produce photon triplets. The wavefunctions of photogenerated excitons localized in these ground states are correlated via molecular hybridization and Coulomb interactions. The formation of a triexciton leads...

    • The superconducting spin valve and triplet superconductivity (United States)

      Garifullin, I. A.; Leksin, P. V.; Garif`yanov, N. N.; Kamashev, A. A.; Fominov, Ya. V.; Schumann, J.; Krupskaya, Y.; Kataev, V.; Schmidt, O. G.; Büchner, B.


      A review of our recent results on the spin valve effect is presented. We have used a theoretically proposed spin switch design F1/F2/S comprising a ferromagnetic bilayer (F1/F2) as a ferromagnetic component, and an ordinary superconductor (S) as the second interface component. Based on it we have prepared and studied in detail a set of multilayers CoOx/Fe1/Cu/Fe2/S (S=In or Pb). In these heterostructures we have realized for the first time a full spin switch effect for the superconducting current, have observed its sign-changing oscillating behavior as a function of the Fe2-layer thickness and finally have obtained direct evidence for the long-range triplet superconductivity arising due to noncollinearity of the magnetizations of the Fe1 and Fe2 layers.

    • Triplet to Singleton-A Successful Outcome

      Directory of Open Access Journals (Sweden)

      Priya Varshney


      Full Text Available We are presenting a case report of triplet pregnancy in a 25 years old lady, in whom single fetal reduction was done at 10 weeks. At 29 weeks, ultrasonography showed fetal demise of second twin. Conservative management was done, after evaluating the status of second twin. Maternal and fetal monitoring was done with PT INR, Ultrasound Doppler weekly till 33 weeks when an emergency cesarean was done due to preterm labour pains. A healthy baby of 1.8 kg was born along with a macerated IUD of 500 gms. Mother and baby are healthy on follow up till date. Hence conservative management should be followed in single fetus demise in twin pregnancy with proper monitoring.

    • Facile Co-Assembly of a Dipeptide-Based Organogel toward Efficient Triplet-Triplet Annihilation Photonic Upconversion. (United States)

      Liu, Xingcen; Fei, Jinbo; Zhu, Pengli; Li, Junbai


      By one-step molecular co-assembly, a diphenylalanine-based photonic upconversion organogel was constructed within 20 seconds. Impressively, such an assembled system exhibits green-to-blue triplet-triplet annihilation upconversion with a relative quantum yield of 12 % even under ambient conditions.

    • ARTICLES: Microwave Assisted Synthesis of a New Triplet Iridium(III) Pyrazine Complex (United States)

      Wu, Qiu-hua; Wang, Chuan-hong; Song, Xi-ming; Zhang, Guo-lin


      A new cyclometalated iridium(III) complex Ir(DPP)3 (DPP = 2,3-diphenylpyrazine) was prepared by reaction of DPP with iridium trichloride hydrate under microwave irradiation. The structure of the complex was confirmed by elemental analysis, 1H NMR, and mass spectroscopy. The UV-Vis absorption and photoluminescent properties of the complex were investigated. The complex shows strong 1MLCT (singlet metal to ligand charge-transfer) and 3MLCT (triplet metal to ligand charge-transfer) absorption at 382 and 504 nm, respectively. The complex also shows strong photoluminescence at 573 nm at room temperature. These results suggest the complex to be a promising phosphorescent material.

    • Pair Triplet Association Rule Generation in Streams

      Directory of Open Access Journals (Sweden)

      Manisha Thool


      Full Text Available Many applications involve the generation and analysis of a new kind of data, called stream data, where data flows in and out of an observation platform or window dynamically. Such data streams have the unique features such as huge or possibly infinite volume, dynamically changing, flowing in or out in a fixed order, allowing only one or a small number of scans. An important problem in data stream mining is that of finding frequent items in the stream. This problem finds application across several domains such as financial systems, web traffic monitoring, internet advertising, retail and e-business. This raises new issues that need to be considered when developing association rule mining technique for stream data. The Space-Saving algorithm reports both frequent and top-k elements with tight guarantees on errors. We also develop the notion of association rules in streams of elements. The Streaming-Rules algorithm is integrated with Space-Saving algorithm to report 1-1 association rules with tight guarantees on errors, using minimal space, and limited processing per element and we are using Apriori algorithm for static datasets and generation of association rules and implement Streaming-Rules algorithm for pair, triplet association rules. We compare the top- rules of static datasets with output of stream datasets and find percentage of error.

    • Triplet pairing in pure neutron matter (United States)

      Srinivas, Sarath; Ramanan, S.


      We study the zero-temperature BCS gaps for the triplet channel in pure neutron matter using similarity renormalization group (SRG) evolved interactions. We use the dependence of the results on the SRG resolution scale as a tool to analyze medium and many-body corrections. In particular, we study the effects of including the three-body interactions at leading order, which appear at next-to-next-to leading order (N2LO) in the chiral effective field theory (EFT), as well as that of the first-order self-energy corrections on the zero-temperature gap. In addition we also extract the transition temperature as a function of densities and verify the BCS scaling of the zero-temperature gaps to the transition temperature. We observe that the self-energy effects are very crucial in order to reduce the SRG resolution scale dependence of the results, while the three-body effects at the leading order do not change the two-body resolution scale dependence. On the other hand, the results depend strongly on the three-body cutoff, emphasizing the importance of the missing higher-order three-body effects. We also observe that self-energy effects reduce the overall gap as well as shift the gap closure to lower densities.

    • Epigenetics and triplet repeat neurological diseases

      Directory of Open Access Journals (Sweden)

      Sathiji eNageshwaran


      Full Text Available The term ‘junk DNA’ has been reconsidered following the delineation of the functional significance of repetitive DNA regions. Typically associated with centromeres and telomeres, DNA repeats are found in nearly all organisms throughout their genomes. Repetitive regions are frequently heterchromatinised resulting in silencing of intrinsic and nearby genes. However, this is not a uniform rule, with several genes known to require such an environment to permit transcription. Repetitive regions frequently exist as dinucleotide, trinucleotide and tetranucleotide repeats. The association between repetitive regions and disease was emphasised following the discovery of abnormal trinucleotide repeats underlying spinal and bulbar muscular atrophy (Kennedy’s disease and fragile X syndrome of mental retardation (FRAXA in 1991. In this review we provide a brief overview of epigenetic mechanisms and then focus on several diseases caused by DNA triplet-repeat expansions, which exhibit diverse epigenetic effects. It is clear that the emerging field of epigenetics is already generating novel potential therapeutic avenues for this group of largely incurable diseases.

    • Triplet Pairing in pure neutron matter

      CERN Document Server

      Srinivas, Sarath


      We study the zero temperature BCS gaps for the triplet channel in pure neutron matter using Similarity Renormalization Group (SRG) evolved interactions. We use the dependence of the results on the SRG resolution scale, as a tool to analyze medium and many-body corrections. In particular, we study the effects of including the three-body interactions at leading order, which appear at N2LO in the Chiral EFT, as well as that of the first-order self-energy corrections on the zero temperature gap. In addition we also extract the transition temperature as a function of densities and verify the BCS scaling of the zero temperature gaps to the transition temperature. We observe that the self-energy effects are very crucial in order to reduce the SRG resolution scale dependence of the results, while the three-body effects at the leading order do not change the two-body resolution scale dependence. On the other hand, the results depend strongly on the three-body cut-off, emphasizing the importance of the missing higher-o...

  1. Rh isoimmunization complicating a triplet gestation. A case report. (United States)

    Gast, M J; Rigg, L A; Martin, C M


    A case occurred of Rh isoimmunization complicating a triplet gestation. Management of that extremely rare situation required careful attention to the problems inherent in both multiple pregnancy and isoimmunization. Amniocentesis and frequent antepartum fetal monitoring were the cornerstones of therapy.

  2. Scalar triplet on a domain wall: an exact solution (United States)

    Gani, Vakhid A.; Lizunova, Mariya A.; Radomskiy, Roman V.


    We study a model with a real scalar Higgs field and a scalar triplet field that allows existence of a topological defect — a domain wall. The wall breaks the global O(3) symmetry of the model, which gives rise to non-Abelian orientational degrees of freedom. We found an exact analytic solution that describes a domain wall with a localized configuration of the triplet field on it. This solution enables one to calculate contributions to the action from the orientational and translational degrees of freedom of the triplet field. We also study the linear stability of the domain wall with the triplet field switched off. We obtain that degrees of freedom localized on the wall can appear or do not appear depending on the parameters of the model.

  3. Higher-Spin Triplet Fields and String Theory

    Directory of Open Access Journals (Sweden)

    D. Sorokin


    Full Text Available We review basic properties of reducible higher-spin multiplets, called triplets, and demonstrate how they naturally appear as part of the spectrum of String Field Theory in the tensionless limit. We show how in the frame-like formulation the triplet fields are endowed with the geometrical meaning of being components of higher-spin vielbeins and connections and present actions describing their free dynamics.

  4. Exploring Hyperchargeless Higgs Triplet Model up to the Planck Scale

    CERN Document Server

    Khan, Najimuddin


    We examine extended Higgs triplet of Standard Model taking into consideration the Higgs-like particle discovery at the LHC with mass around 125 GeV. We evaluate the bounds on the scalar potential through the unitarity of the scattering-matrix. Considering with and without $Z_2$-symmetry on the extra triplet, we derive constraints on the parameter space. We identify the region of the parameter space that corresponds to the stability and metastability of the electroweak vacuum.

  5. Ca(II, Zn(II and Au(III sulfamethoxazole sulfa-drug complexes: Synthesis, spectroscopic and anticancer evaluation studies

    Directory of Open Access Journals (Sweden)

    Fatima A.I. Al-Khodir


    Full Text Available Herein in this article, three new Ca(II, Zn(II and Au(III complexes of sulfamethoxazole (SZ (sulfa-drug have been synthesized for the first time. The sulfa-drugs have a great attentions because of their therapeutic applications against bacterial infections. The SZ complexes were discussed with the help of elemental analyses, molar conductance and spectroscopic instruments e.g. IR, 1H-NMR, and electronic spectra. Investigations of the infrared spectra of the SZ and their metal complexes indicated the vibrations due to the sulfonamido (SO2 and –NH and isoxazole (C=N groups are shifted with respect to the free molecule in line with their coordination to the metal. In case of calcium(II an zinc(II complexes, the coordination site of SZ are the sulfonyl oxygen and SO2-NH sulfonamide nitrogen, but in gold(III complex, the gold metal ions coordinates through the sulfonyl oxygen and isoxazole nitrogen. These complexes are formulated as: [Ca(SZ(Cl2].8H2O (1, [Zn(SZ(Cl2].2H2O (2 and [Au(SZ(Cl2].Cl (3. The molar conductance data reveals that both Ca(II and Zn(II complexes are non-electrolyte but gold(III complex is electrolyte. The morphological nano structures of SZ complexes were checked using X-ray powder diffraction (XRD, scanning electron microscope (SEM and transmission electron microscopy (TEM. The gold(III complex was recorded good anticancer behavior against Human colon carcinoma (HCT-116 cells and human hepatocellular carcinoma (HepG-2 cells.

  6. Improving triplet-triplet-annihilation based upconversion systems by tuning their topological structure. (United States)

    Zimmermann, Jochen; Mulet, Roberto; Scholes, Gregory D; Wellens, Thomas; Buchleitner, Andreas


    Materials capable to perform upconversion of light transform the photon spectrum and can be used to increase the efficiency of solar cells by upconverting sub-bandgap photons, increasing the density of photons able to generate an electron-hole pair in the cell. Incoherent solar radiation suffices to activate upconverters based on sensitized triplet-triplet annihilation, which makes them particularly suited for this task. This process requires two molecular species, sensitizers absorbing low energy photons, and emitters generating higher frequency photons. Successful implementations exist in solutions and solids. However, solid upconverters exhibit lower efficiency than those in solution, which poses a serious problem for real applications. In the present work, we suggest a new strategy to increase the efficiency of sensitized upconverters that exploits the solid nature of the material. We show that an upconversion model system with molecules distributed as clusters outperforms a system with a random distribution of molecules, as used in current upconverters. Our simulations reveal a high potential for improvement of upconverter systems by exploring different structural configurations of the molecules. The implementation of advanced structures can push the performance of solid upconverters further towards the theoretical limit and a step closer to technological application of low power upconversion.

  7. Birth weight discordance and perinatal mortality among triplets

    Directory of Open Access Journals (Sweden)

    Egić Amira


    Full Text Available INTRODUCTION. The incidence of multiple births has increased in the last decade. Perinatal mortality in triplets is significantly greater than in twin and singleton births. OBJECTIVE. The objective of this study was to describe the extent of birth weight discordance among triplets and to identify its association with an increased risk of perinatal mortality. METHOD A retrospective analysis of triplet births, for the period 1993-2003, was conducted at the Gynaecological-Obstetric Clinic "Narodni Front" in Belgrade. Birth weight discordance was defined as the difference in birth weight between the largest and the smallest triplet's weight of more than 20%. RESULTS. The rate of triplets has increased by almost 75% between the first (7.7% and the last (29.6% 5-year period of the last decade. Triplets are becoming more common because of the frequent use of assisted reproductive technology as a treatment for infertility. In the period 1993-2003, there were a total of 40 triplet live births (24 weeks and greater with incidence of 0.06%. There was no clear association between maternal age, parity, method of conception, birth gestational age, and disorders complicating pregnancy with birth discordance more than 20%. Regarding birth weight groups, statistical significance occurred only in the <999 grams group for discordant and in the 2000-2499 grams group for concordant triplets. Overall, the perinatal mortality rate in the group was 10.8%, the foetal mortality rate was 1.7% (2/120, and the neonatal (0-28 days mortality rate was 9.1% (11/120. An odds ratio of 95% confidence interval shows 3 times greater risk for adverse perinatal outcome in the discordant group. However, the difference was not significant. CONCLUSION. Increasing birth weight discordance may increase the risk of adverse perinatal outcome. Triplet pregnancies, being high risk, require intensive antenatal care in order to prevent preterm delivery and ultrasound in order to diagnose foetal

  8. Rates and singlet/triplet ratios from TADF transients

    CERN Document Server

    Nelson, Mitchell C


    Thermally activated delayed fluorescence has been reported in a number of OLED emitter materials engineered to have low singlet-triplet energy gaps. Here we derive closed solutions for steady state and transient behaviors and apply these results to data provided in recent reports. Earlier work has used yields, rates and a supplied forward crossing rate to estimate the reverse crossing rate and then obtain the singlet-triplet energy gap in a log-linear fit. In this work we use only the system relaxation times and obtain all five of the system constants: the singlet and triplet relaxation rates, the forward and reverse crossing rates and the singlet-triplet energy gap. These are then used to calculate the fluorescent/phosphorescent ratio and the singlet/triplet population ratio. Good fits are obtained for data from 4CzIPN and from the excimer m-MTDATA:t-Bu-PBD and the results appear to be consistent with the reported behaviors of OLEDS using these materials.

  9. Ion-Pair States in Triplet Molecular Hydrogen (United States)

    Setzer, W.; Baker, B. C.; Ashman, S.; Morgan, T. J.


    An experimental search is underway to observe the long range triplet ionic states H+ H- of molecular hydrogen. Resonantly enhanced multi-photon ionization of the metastable c 3∏u- 2 pπ state is used access to the R(1)nd1 n = 21 Rydberg state that serves as an intermediate stepping stone state to probe the energy region above the ionization limit with a second tunable laser photon. The metastable state is prepared by electron capture of 6 keV H2+ions in potassium in a molecular beam. Formation of the H+ H- triplet configuration involves triplet excited states of the H- ion, especially the 2p23Pe state, the second bound state of H- predicted to exist with a lifetime long compared to typical auto ionization lifetimes but not yet observed experimentally. Details of the experiment and preliminary results to date will be presented at the conference.

  10. Leptogenesis, radiative neutrino masses and inert Higgs triplet dark matter

    CERN Document Server

    Lu, Wen-Bin


    We extend the standard model by three types of inert fields including Majorana fermion singlets/triplets, real Higgs singlets/triplets and leptonic Higgs doublets. In the presence of a softly broken lepton number and an exactly conserved Z_2 discrete symmetry, these inert fields together can mediate a one-loop diagram for a Majorana neutrino mass generation. The heavier inert fields can decay to realize a successful leptogenesis while the lightest inert field can provide a stable dark matter candidate. As an example, we demonstrate the leptogenesis by the inert Higgs doublet decays. We also perform a systematic study on the inert Higgs triplet dark matter scenario where the interference between the gauge and Higgs portal interactions can significantly affect the dark matter properties.

  11. Fat Branes, Orbifolds and Doublet-Triplet Splitting

    CERN Document Server

    Haba, N; Haba, Naoyuki; Maru, Nobuhito


    A simple higher dimensional mechanism of the doublet-triplet splitting is presented in a five dimensional supersymmetric SU(5) GUT on S^1/Z_2. The splitting of multiplets is realized by a VEV of the adjoint chiral superfield which breaks SU(5) gauge symmetry. Depending on the sign of the VEV, zero mode Higgs doublets and triplets are localized on the either side of the fixed points. The mass splitting is realized due to the difference of magnitudes of the overlap with a brane localized or a bulk singlet field. No unnatural fine-tuning of parameters is needed. The proton stability is ensured by locality {em without symmetries}. As well as a conventional mass splitting solution, it is shown that the weak scale Higgs triplet is consistent with the proton stability. This result might provide an alternative signature of GUT in future collider experiments.


    Energy Technology Data Exchange (ETDEWEB)

    Del Pino Alemán, Tanausú; Trujillo Bueno, Javier [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)


    We present multilevel radiative transfer modeling of the scattering polarization observed in the solar O i infrared triplet around 777 nm. We demonstrate that the scattering polarization pattern observed on the solar disk forms in the chromosphere, far above the photospheric region where the bulk of the emergent intensity profiles originate. We investigate the sensitivity of the polarization pattern to the thermal structure of the solar atmosphere and to the presence of weak magnetic fields (10{sup −2}–100 G) through the Hanle effect, showing that the scattering polarization signals of the oxygen infrared triplet encode information on the magnetism of the solar chromosphere.

  13. Chromospheric Polarization in the Photospheric Solar Oxygen Infrared Triplet

    CERN Document Server

    Alemán, T del Pino


    We present multilevel radiative transfer modeling of the scattering polarization observed in the solar O I infrared triplet around 777 nm. We demonstrate that the scattering polarization pattern observed on the solar disk forms in the chromosphere, far above the photospheric region where the bulk of the emergent intensity profiles originates. We study the sensitivity of the polarization pattern to the thermal structure of the solar atmosphere and to the presence of weak magnetic fields (0.01 - 100 G) through the Hanle effect, showing that the scattering polarization signals of the oxygen infrared triplet encode information on the magnetism of the solar chromosphere.

  14. Network realization of triplet-type quantum stochastic systems (United States)

    Zhou, Shaosheng; Fu, Shizhou; Chen, Yuping


    This paper focuses on a problem of network synthesis for a class of quantum stochastic systems. The systems under consideration are of triplet-type form and stem from linear quantum optics and linear quantum circuits. A new quantum network realization approach is proposed by generalizing the scattering operator from the scalar form to a unitary matrix in network components. It shows that the triplet-type quantum stochastic system can be approximated by a quantum network which consists of some one-degree-of-freedom generalized open-quantum harmonic oscillators (1DGQHOs) via series, concatenation and feedback connections.

  15. Effective t-J model of pairing: singlet versus triplet

    Directory of Open Access Journals (Sweden)



    Full Text Available The t-J model is regarded as a canonical model of spin-singlet pairing induced by the kinetic exchange interaction also responsible for an antiferromagnetic ordering in the strongly correlated narrow-band systems. In the orbitally degenerate systems both ferromagnetic and antiferromagnetic kinetic exchange interactions occur. I briefly review the analogy between the singlet and triplet types of pairing, as well as draw some general conclusions about the pairing induced by these exchange interactions. The general discussion is also illustrated with a concrete case of a two-dimensional lattice with the spin triplet pairing.

  16. Selective chelation of Cd(II) and Pb(II) versus Ca(II) and Zn(II) by using octadentate ligands containing pyridinecarboxylate and pyridyl pendants. (United States)

    Ferreirós-Martínez, Raquel; Esteban-Gómez, David; Platas-Iglesias, Carlos; de Blas, Andrés; Rodríguez-Blas, Teresa


    Herein we report the coordination properties toward Cd(II), Pb(II), Ca(II), and Zn(II) of a new octadentate ligand (py-H(2)bcpe) based on a ethane-1,2-diamine unit containing two picolinate and two pyridyl pendants, which is structurally derived from the previous reported ligand bcpe. Potentiometric studies have been carried out to determine the protonation constants of the ligand and the stability constants of the complexes with these cations. The introduction of the pyridyl pendants in bcpe provokes a very important increase of the logK(ML) values obtained for the Pb(II) and Cd(II) complexes, while this effect is less important in the case of the Zn(II) analogue. As a result, py-bcpe shows a certain selectivity for Cd(II) and Pb(II) over Zn(II) while keeping good Pb(II)/Ca(II) and Cd(II)/Ca(II) selectivities, and the new receptor py-bcpe can be considered as a new structural framework for the design of novel Cd(II) and Pb(II) extracting agents. Likewise, the stabilities of the Cd(II) and Pb(II) complexes are higher than those of the corresponding EDTA analogues. The X-ray crystal structure of [Zn(py-bcpe)] shows hexadentate binding of the ligand to the metal ion, the coordination polyhedron being best described as a severely distorted octahedron. However, the X-ray crystal structure of the Pb(II) analogue shows octadentate binding of the ligand to the metal ion. A detailed investigation of the structure in aqueous solution of the complexes by using nuclear magnetic resonance (NMR) techniques and density functional theory (DFT) calculations (B3LYP) shows that while in the Zn(II) complex the metal ion is six-coordinated, in the Pb(II) and Ca(II) analogues the metal ions are eight-coordinated. For the Cd(II) complex, our results suggest that in solution the complex exists as a mixture of seven- and eight-coordinated species. DFT calculations performed both in the gas phase and in aqueous solution have been also used to investigate the role of the Pb(II) lone pair in

  17. Non-conventional halide oxidation pathways : oxidation by imidazole triplet and surface specific oxidation by ozone (United States)

    Ammann, Markus; Corral-Arroyo, Pablo; Aellig, Raphael; Orlando, Fabrizio; Lee, Ming-Tao; Artiglia, Luca


    Oxidation of halide ions (chloride, bromide, iodide) are the starting point of halogen release mechanisms out of sea water, marine aerosol or other halide containing continental aerosols. Slow oxidation of chloride and bromide by ozone in the bulk aqueous phase is of limited relevance. Faster surface specific oxidation has been suggested based on heterogeneous kinetics experiments. We provide first insight into very efficient bromide oxidation by ozone at the aqueous solution - air interface by surface sensitive X-ray photoelectron spectroscopy indicating significant build-up of an oxidized intermediate at the surface within millisecond time scales. The second source of oxidants in the condensed we have considered is the absorption of light by triplet forming photosensitizers at wavelengths longer than needed for direct photolysis and radical formation. We have performed coated wall flow tube experiments with mixtures of citric acid (CA) and imidazole-2-carboxaldehyde (IC) to represent secondary organic material rich marine aerosol. The halide ions bromide and iodide have been observed to act as efficient electron donors leading to their oxidation, HO2 formation and finally release of molecular halogen compounds. The photosensitization of imidazole-2-carboxaldehyde (IC) involves a well-known mechanism where the triplet excited state of IC is reduced by citric acid to a reduced ketyl radical that reacts with halide ions. A competition kinetics approach has been used to evaluate the rate limiting steps and to assess the significance of this source of halogens to the gas phase.

  18. Pyridine-2,6-diyl dinitroxides as room-temperature triplet ligands

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Hinako; Tonegawa, Asato; Ishida, Takayuki, E-mail: [Department of Engineering Science, The University of Electro-Communications, Tokyo (Japan)


    We have proposed tert-butyl 2-pyridyl nitroxide radicals as a promising paramagnetic chelating ligand, where the direct radical-metal bond leads to strong magnetic interaction. We successfully synthesized and isolated PyBN derivatives (pyridine-2,6-diyl bis(tert-butyl nitroxides)). The molecular and crystal structures of the target biradicals, MesPyBN, AntPyBN and tBuOPyBN were determined from the X-ray crystal structure analysis, which possess mesityl, 9-anthryl and tert-butoxy groups at the 5-position of the pyridine ring, respectively. The ground triplet state was characterized by means of SQUID susceptometry for each compound. On heating, the χ{sub m}T values of all the PyBN derivatives increased and reached a plateau at ca. 1.0 cm{sup 3} K mol{sup −1} at 300 K. It implies that biradicals behaved as triplet molecules even at room temperature, or 2J/k{sub B} >> 300 K. From the decay monitored in solution electron-spin resonance spectroscopy, MesPyBN was the most persistent, while tBuOPyBN was the most reactive, of the three.

  19. High-efficiency fluorescent organic light-emitting diodes enabled by triplet-triplet annihilation and horizontal emitter orientation

    Energy Technology Data Exchange (ETDEWEB)

    Mayr, Christian, E-mail:; Schmidt, Tobias D.; Brütting, Wolfgang, E-mail: [Institute of Physics, University of Augsburg, 86135 Augsburg (Germany)


    A green organic light-emitting diode with the fluorescent emitter Coumarin 545T shows an external quantum efficiency (η{sub EQE}) of 6.9%, clearly exceeding the classical limit of 5% for fluorescent emitters. The analysis of the angular dependent photoluminescence spectrum of the emission layer reveals that 86% of the transition dipole moments are horizontally oriented. Furthermore, transient electroluminescence measurements demonstrate the presence of a delayed emission originating from triplet-triplet annihilation. A simulation based efficiency analysis reveals quantitatively the origin for the high η{sub EQE}: a radiative exciton fraction higher than 25% and a light-outcoupling efficiency of nearly 30%.

  20. New sets of experimental wavenumber values for triplet-triplet rovibronic transitions of $H_2$ and $D_2$

    CERN Document Server

    Lavrov, Boris P; Umrikhin, Ivan S


    New sets of experimental wavenumber values for triplet-triplet rovibronic transitions of $H_2$ and $D_2$ for visible part of spectrum ($400 \\div 700$ nm) have been obtained. The digital intensity registration providing a linear response of the detector gave us the opportunity of digital deconvolution of the recorded line profiles. For line centers that made it possible to reach an accuracy limited only by selfconsistency of various wavenumber standards. New set of data was obtained with accuracy $0.006 \\div 0.05$ cm$^{-1}$.

  1. Intramolecular triplet energy transfer in anthracene-based platinum acetylide oligomers. (United States)

    Li, Yongjun; Köse, Muhammet E; Schanze, Kirk S


    Platinum acetylide oligomers that contain an anthracene moiety have been synthesized and subjected to photophysical characterization. Spectroscopic measurement and DFT calculations reveal that both the singlet and triplet energy levels of the anthracene segment are lower than those of the platinum acetylide segment. Thus, the platinum acetylide segment acts as a sensitizer to populate the triplet state of the anthrancene segment via intramolecular triplet-triplet energy transfer. The objective of this work is to understand the mechanisms of energy-transfer dynamics in these systems. Fluorescence quenching and the dominant triplet absorption that arises from the anthracene segment in the transient absorption spectrum of Pt4An give clear evidence that energy transfer adopts an indirect mechanism, which begins with singlet-triplet energy transfer from the anthracene segment to the platinum acetylide segment followed by triplet-triplet energy transfer to the anthracene segment.

  2. Ca(II) doped β-In2S3 hierarchical structures for photocatalytic hydrogen generation and organic dye degradation under visible light irradiation. (United States)

    Yang, Shuang; Xu, Cheng-Yan; Zhang, Bao-You; Yang, Li; Hu, Sheng-Peng; Zhen, Liang


    Hierarchical structures assembled by two-dimensional (2D) nanosheets could inherit the characteristics of nanosheets and acquire additional advantages from the unique secondary architectures, which would have important influences on the photocatalytic properties of semiconductor nanomaterials. In this work, we successfully synthesized Ca(II) doped β-In2S3 hierarchical structures stacked by thin nanosheets by a simple solution chemical process. The effects of reaction temperature and Ca(2+) concentration on the size and morphology of the products were systematically investigated. The photocatalytic applications of the β-In2S3 hierarchical structures were evaluated for hydrogen production and degradation of Rhodamine B (RhB) under visible light irradiation (λ>420nm). The β-In2S3 hierarchical structures showed promising activity towards photocatalytic hydrogen production (145.0μmolg(-1)h(-1)) and RhB solution (1×10(-5)M) was completely degraded within 100min under visible light irradiation.

  3. Triplet State Resonance Raman Spectrum of all-trans-diphenylbutadiene

    DEFF Research Database (Denmark)

    Wilbrandt, Robert Walter; Grossman, W.E.L.; Killough, P.M;


    The resonance Raman spectrum of all-trans-diphenylbutadiene (DPB) in its ground state and the resonance Raman spectrum (RRS) of DPB in its short-lived electronically excited triplet state are reported. Transient spectra were obtained by a pump-probe technique using two pulsed lasers. The prereson...

  4. Mirror and triplet displacement energies within nuclear DFT: numerical stability

    CERN Document Server

    Baczyk, Pawel; Konieczka, Maciej; Nakatsukasa, Takashi; Sato, Koichi; Satula, Wojciech


    Isospin-symmetry-violating class II and III contact terms are introduced into the Skyrme energy density functional to account for charge dependence of the strong nuclear interaction. The two new coupling constants are adjusted to available experimental data on triplet and mirror displacement energies, respectively. We present preliminary results of the fit, focusing on its numerical stability with respect to the basis size.

  5. Properties of the Triplet State of Coumarin Substituted Compounds (United States)

    Bryantseva, N. G.; Gadirov, R. M.; Nikonov, S. Yu.; Sokolova, I. V.


    The absorption spectra of the triplet excited state of coumarin sensitizers are investigated both theoretically and experimentally. The most intense triplet-triplet (TT) absorption bands are determined. The experimental spectra of the T-T absorption are compared with the theoretical T-T transitions. The phosphorescence spectra of five compounds are measured at a temperature of 77 K. The quantum phosphorescence yield is determined by the method of comparison with an etalon (8-methoxypsoralen). The phosphorescence lifetime is determined for the examined molecules at a temperature of 77 K. For 3,4-phenyl-4',5'-cyclohexylpsoralen, 4'-methyl-3,4-cycloheptylpsoralen, and 4'5'-dimethyl-3,4-cyclohexylpsoralen compounds, this time is equal to 1.1, 1.25, and 2.5 s, respectively. The main energy deactivation channel for all examined compounds is the phosphorescence. The positions of the lower excited triplet states, calculated by the quantum-chemical method of intermediate neglect of differential overlap with spectroscopic parameterization (INDO/S), are confirmed by the available experimental data.

  6. Stability of singlet and triplet trions in carbon nanotubes

    DEFF Research Database (Denmark)

    Rønnow, Troels Frimodt; Pedersen, Thomas Garm; Cornean, Horia


    We investigate singlet and triplet trion states in semiconducting carbon nanotubes using a one-dimensional model. It is concluded that singlet trion states in bind up to 13.5% stronger than exciton states, and that they lower the optical transition energy with up to 50% of the tight binding band ...

  7. Vector-like quarks with a scalar triplet

    CERN Document Server

    Leskow, Estefania Coluccio; de la Puente, Alejandro


    We study a model independent extension to the Standard Model with an addi- tional real scalar triplet, {\\Sigma}, and a single vector-like quark, T . This class of models appear naturally in extensions of the Littlest Higgs model that incorporate dark matter without the need of T -parity. We assume that the triplet does not develop a vacuum expectation value and that all dimension five operators coupling the triplet to Standard Model fields and the vector-like quarks are parametrized by the scale {\\Lambda} at which we expect new physics to arise. We introduce new non-renormalizable interactions between the new scalar sector and fermion sector that allow mixing between the Standard Model third generation up-type quark and the vector-like quark in a way that leads to the cancellation of the leading quadratic divergences to the one-loop corrections to the mass of the Higgs boson. Within this framework, new de- cay modes of the vector-like quark to the real scalar triplet and SM particles arise and bring forth an ...

  8. Vector-like quarks with a scalar triplet

    Directory of Open Access Journals (Sweden)

    Estefania Coluccio Leskow


    Full Text Available We study a minimal extension to the Standard Model with an additional real scalar triplet, Σ, and a single vector-like quark, T. This class of models appear naturally in extensions of the Littlest Higgs model that incorporate dark matter without the need of T-parity. We assume the limit that the triplet does not develop a vacuum expectation value and that all dimension five operators coupling the triplet to Standard Model fields and the vector-like quarks are characterized by the scale Λ at which we expect new physics to arise. We introduce new non-renormalizable interactions between the new scalar sector and fermion sector that allow mixing between the Standard Model third generation up-type quark and the vector-like quark in a way that leads to the cancellation of the leading quadratic divergences to the one-loop corrections from the top quark to the mass of the Higgs boson. Within this framework, new decay modes of the vector-like quark to the real scalar triplet and SM particles arise and bring forth an opportunity to probe this model with existing and future LHC data. We contrast constraints from direct colliders searches with low energy precision measurements and find that heavy vector-like top quarks with a mass as low as 650 GeV are consistent with current experimental constraints in models where new physics arises at scales below 2 TeV.

  9. The fragment spin difference scheme for triplet-triplet energy transfer coupling. (United States)

    You, Zhi-Qiang; Hsu, Chao-Ping


    To calculate the electronic couplings in both inter- and intramolecular triplet energy transfer (TET), we have developed the "fragment spin difference" (FSD) scheme. The FSD was a generalization from the "fragment charge difference" (FCD) method of Voityuk et al. [J. Chem. Phys. 117, 5607 (2002)] for electron transfer (ET) coupling. In FSD, the spin population difference was used in place of the charge difference in FCD. FSD is derived from the eigenstate energies and populations, and therefore the FSD couplings contain all contributions in the Hamiltonian as well as the potential overlap effect. In the present work, two series of molecules, all-trans-polyene oligomers and polycyclic aromatic hydrocarbons, were tested for intermolecular TET study. The TET coupling results are largely similar to those from the previously developed direct coupling scheme, with FSD being easier and more flexible in use. On the other hand, the Dexter's exchange integral value, a quantity that is often used as an approximate for the TET coupling, varies in a large range as compared to the corresponding TET coupling. To test the FSD for intramolecular TET, we have calculated the TET couplings between zinc(II)-porphyrin and free-base porphyrin separated by different numbers of p-phenyleneethynylene bridge units. Our estimated rate constants are consistent with experimentally measured TET rates. The FSD method can be used for both intermolecular and intramolecular TET, regardless of their symmetry. This general applicability is an improvement over most existing methodologies.

  10. The fragment spin difference scheme for triplet-triplet energy transfer coupling (United States)

    You, Zhi-Qiang; Hsu, Chao-Ping


    To calculate the electronic couplings in both inter- and intramolecular triplet energy transfer (TET), we have developed the "fragment spin difference" (FSD) scheme. The FSD was a generalization from the "fragment charge difference" (FCD) method of Voityuk et al. [J. Chem. Phys. 117, 5607 (2002)] for electron transfer (ET) coupling. In FSD, the spin population difference was used in place of the charge difference in FCD. FSD is derived from the eigenstate energies and populations, and therefore the FSD couplings contain all contributions in the Hamiltonian as well as the potential overlap effect. In the present work, two series of molecules, all-trans-polyene oligomers and polycyclic aromatic hydrocarbons, were tested for intermolecular TET study. The TET coupling results are largely similar to those from the previously developed direct coupling scheme, with FSD being easier and more flexible in use. On the other hand, the Dexter's exchange integral value, a quantity that is often used as an approximate for the TET coupling, varies in a large range as compared to the corresponding TET coupling. To test the FSD for intramolecular TET, we have calculated the TET couplings between zinc(II)-porphyrin and free-base porphyrin separated by different numbers of p-phenyleneethynylene bridge units. Our estimated rate constants are consistent with experimentally measured TET rates. The FSD method can be used for both intermolecular and intramolecular TET, regardless of their symmetry. This general applicability is an improvement over most existing methodologies.

  11. The Ca II triplet in red giant spectra: [Fe/H] determinations and the role of [Ca/Fe

    CERN Document Server

    Da Costa, G S


    Measurements are presented and analyzed of the strength of the Ca II triplet lines in red giants in Galactic globular and open clusters, and in a sample of red giants in the LMC disk that have significantly different [Ca/Fe] abundance ratios to the Galactic objects. The Galactic objects are used to generate a calibration between Ca II triplet line strength and [Fe/H], which is then used to estimate [Fe/H]_CaT for the LMC stars. The values are then compared with the [Fe/H]_spec determinations from high dispersion spectroscopy. After allowance for a small systematic offset the two abundance determinations are in excellent agreement. Further, as found in earlier studies, e.g., Battaglia et al. (2008), the difference is only a very weak function of the [Ca/Fe] ratio. For example, changing [Ca/Fe] from +0.3 to -0.2 causes the Ca II based abundance to underestimate [Fe/H]_spec by only ~0.15 dex, assuming a Galactic calibration. Consequently, the Ca II triplet approach to metallicity determinations can be used witho...

  12. Spontaneous fluctuations of transition dipole moment orientation in OLED triplet emitters

    CERN Document Server

    Steiner, Florian; Vogelsang, Jan; Lupton, John M


    The efficiency of an organic light-emitting diode (OLED) depends on the microscopic orientation of transition dipole moments of the molecular emitters. The most effective materials used for light generation have threefold symmetry, which prohibit a priori determination of dipole orientation due to the degeneracy of the fundamental transition. Single-molecule spectroscopy reveals that the model triplet emitter tris(2-phenylisoquinoline)iridium(III) (Ir(piq)3) does not behave as a linear dipole, radiating with lower polarization anisotropy than expected. Spontaneous symmetry breaking occurs in the excited state, leading to a random selection of one of the three ligands to form a charge transfer state with the metal. This non-deterministic localization is revealed in switching of the degree of linear polarization of phosphorescence. Polarization scrambling likely raises out-coupling efficiency and should be taken into account when deriving molecular orientation of the guest emitter within the OLED host from ense...

  13. Spontaneous Fluctuations of Transition Dipole Moment Orientation in OLED Triplet Emitters. (United States)

    Steiner, Florian; Bange, Sebastian; Vogelsang, Jan; Lupton, John M


    The efficiency of an organic light-emitting diode (OLED) depends on the microscopic orientation of transition dipole moments of the molecular emitters. The most effective materials used for light generation have 3-fold symmetry, which prohibits a priori determination of dipole orientation due to the degeneracy of the fundamental transition. Single-molecule spectroscopy reveals that the model triplet emitter tris(1-phenylisoquinoline)iridium(III) (Ir(piq)3) does not behave as a linear dipole, radiating with lower polarization anisotropy than expected. Spontaneous symmetry breaking occurs in the excited state, leading to a random selection of one of the three ligands to form a charge-transfer state with the metal. This nondeterministic localization is revealed in switching of the degree of linear polarization of phosphorescence. Polarization scrambling likely raises out-coupling efficiency and should be taken into account when deriving molecular orientation of the guest emitter within the OLED host from ensemble angular emission profiles.

  14. Intramolecular triplet energy transfer via higher triplet excited state during stepwise two-color two-laser irradiation. (United States)

    Oseki, Yosuke; Fujitsuka, Mamoru; Sakamoto, Masanori; Majima, Tetsuro


    We studied the energy transfer processes in the molecular array consisting of pyrene (Py), biphenyl (Ph2), and bisphthalimidethiophene (ImT), (Py-Ph2)2-ImT, during two-color two-laser flash photolysis (2-LFP). The first laser irradiation predominantly generates ImT in the lowest triplet excited state (ImT(T1)) because of the efficient singlet energy transfer from Py in the lowest singlet excited state to ImT and, then, intersystem crossing of ImT. ImT(T1) was excited to the higher triplet excited state (Tn) with the second laser irradiation. Then, the triplet energy was rapidly transferred to Py via a two-step triplet energy transfer (TET) process through Ph2. The efficient generation of Py(T1) was suggested from the nanosecond-picosecond 2-LFP. The back-TET from Py(T1) to ImT was observed for several tens of microseconds after the second laser irradiation. The estimated intramolecular TET rate from Py(T1) to ImT was as slow as 3.1 x 104 s-1. Hence, long-lived Py(T1) was selectively and efficiently produced during the 2-LFP.

  15. X-Shooter spectroscopy of young stellar objects III. Photospheric and chromospheric properties of Class III objects

    CERN Document Server

    Stelzer, B; Alcala, J M; Manara, C F; Biazzo, K; Covino, E; Rigliaco, E; Testi, L; Covino, S; D'Elia, V


    We analyzed X-Shooter/VLT spectra of 24 ClassIII sources from three nearby star-forming regions (sigmaOrionis, LupusIII, and TWHya). We determined the effective temperature, surface gravity, rotational velocity, and radial velocity by comparing the observed spectra with synthetic BT-Settl model spectra. We investigated in detail the emission lines emerging from the stellar chromospheres and combined these data with archival X-ray data to allow for a comparison between chromospheric and coronal emissions. Both X-ray and Halpha luminosity as measured in terms of the bolometric luminosity are independent of the effective temperature for early-M stars but decline toward the end of the spectral M sequence. For the saturated early-M stars the average emission level is almost one dex higher for X-rays than for Halpha: log(L_x/L_bol) = -2.85 +- 0.36 vs. log(L_Halpha/L_bol) = -3.72 +- 0.21. When all chromospheric emission lines (including the Balmer series up to H11, CaII HK, the CaII infrared triplet, and several HeI...

  16. A Laser Photolysis Study of Triplet Lifetimes and of Triplet–Triplet Annihilation Reactions of Phthalocyanins in DMSO Solutions (Etude des Durées de Vie du Triplet et des Réactions d'Annihilation Triplet–Triplet de Phthalocyanines dans le DMSO par Photolyse Laser)


    Debacker, M. G.; Deleplanque, O.; Van Vlierberge, B.; Sauvage, F. X.


    Triplet decay of Mg and Zn phthalocyanins have been studied by laser flash photolysis as a function of concentration. The triplet decay mechanism changes from a near first order in dilute solution to an almost second order in concentrated solutions. This is interpreted in terms of triplet–triplet recombinaison. With the help of a reducing agent, it is shown that the triplet–triplet reaction can lead to charge separation.La décroissance des états excités triplet des phthalocyanines de Mg et de...

  17. Heats of Formation of Triplet Ethylene, Ethylidene, and Acetylene

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, M.T.; Matus, M.H.; Lester Jr, W.A.; Dixon, David A.


    Heats of formation of the lowest triplet state of ethylene and the ground triplet state of ethylidene have been predicted by high level electronic structure calculations. Total atomization energies obtained from coupled-cluster CCSD(T) energies extrapolated to the complete basis set limit using correlation consistent basis sets (CBS), plus additional corrections predict the following heats of formation in kcal/mol: Delta H0f(C2H4,3A1) = 80.1 at 0 K and 78.5 at 298 K, and Delta H0f(CH3CH,3A") = 86.8 at 0 K and 85.1 at 298 K, with an error of less than +-1.0 kcal/mol. The vertical and adiabatic singlet-triplet separation energies of ethylene were calculated as Delta ES-T,vert = 104.1 and Delta ES-T,adia = 65.8 kcal/mol. These results are in excellent agreement with recent quantum Monte Carlo (DMC) values of 103.5 +- 0.3 and 66.4 +- 0.3 kcal/mol. Both sets of computational values differ from the experimental estimate of 58 +- 3 kcal/mol for the adiabatic splitting. The computed singlet-triplet gap at 0 K for acetylene is Delta ES-T,adia(C2H2) = 90.5 kcal/mol, which is in notable disagreement with the experimental value of 82.6 kcal/mol. The heat of formation of the triplet is Delta H0f(C2H2,3B2) = 145.3 kcal/mol. There is a systematic underestimation of the singlet-triplet gaps in recent photodecomposition experiments by ~;;7 to 8 kcal/mol. For vinylidene, we predict Delta H0f(H2CC,1A1) = 98.8 kcal/mol at 298 K (exptl. 100.3 +- 4.0), Delta H0f(H2CC,3B2) = 146.2 at 298 K, and an energy gap Delta ES-T-adia(H2CC) = 47.7 kcal/mol.

  18. Measuring oxygen pressures using triplet quenching of Pd-porphine (United States)

    Sinaasappel, Michiel; Ince, C.; Sanderse, E. A.; Bruining, Hajo A.


    A non-invasive optical method for measuring free oxygen in vivo is described. The method, introduced by Wilson and co-workers, is based on the quenching of the triplet state of Pd- porphine by oxygen and is described by the Stern-Volmer relation. The quenching of the triplet state is determined by measurement of the phosphorescence decay following excitation by a pulse of light. Measuring decay times has the advantage that they are independent of the changing optical properties of tissue and concentration of the dye. We describe a setup to measure the phosphorescence decay and present the values of Kq and (tau) o as a function of pH and temperature. Furthermore, some experiments on a rat liver and gut are presented.

  19. Role of triplet polaron pairs in conjugated polymer photophysics (United States)

    Wesely, Elizabeth; Rothberg, Lewis; Marchetti, Alfred; Chen, Shaw; Geng, Yanhou; Culligan, Sean


    We measure the decay of the long-lived fluorescence of a conjugated oligofluorene at temperatures from 300 K to 20 K. We conclude that nearly all of this emission arises from geminate recombination of photogenerated polaron pairs to reform the singlet exciton, and that charge pair recombination represents a significant contribution to the overall fluorescence quantum yield. The unusual nonmonotonic decay dynamics of the delayed fluorescence can be explained if we assume interconversion between singlet and triplet polaron pairs on the submicrosecond time scale. (˜500 ns.) We are able to model the decay of the delayed fluorescence by assuming activated recombination from a Gaussian energy distribution of singlet polaron pairs centered 0.2 eV below the excited state and having a standard deviation of 0.12 eV. The model is relevant to recent work involving the measurement of singlet-triplet branching ratios and to the yields of electroluminescent devices.

  20. Nonradiative formation of the positron-helium triplet bound state (United States)

    di Rienzi, Joseph; Drachman, Richard J.


    We have previously calculated the cross section for radiative formation of the interesting bound state consisting of a positron bound to helium, where the atomic electrons are in the triplet spin state. That process uses the metastable triplet helium system as target, and, as expected, it has a very small cross section. In this paper we examine a more probable process in which the state of interest is produced in an exchange rearrangement collision between a positronium atom and the singlet helium ground state: Ps+He(Se1)→PsHe+(Se3)+e- . The present calculation is done in the plane-wave Born approximation, using simple initial and final wave functions and compares post and prior forms.

  1. Theoretical Investigation on Triplet Excitation Energy Transfer in Fluorene Dimer

    Institute of Scientific and Technical Information of China (English)

    Yu-bing Si; Xin-xin Zhong; Wei-wei Zhang; Yi Zhao


    Triplet-triplet energy transfer in fluorene dimer is investigated by combining rate theories with electronic structure calculations.The two key parameters for the control of energy transfer,electronic conpling and reorganization energy,are calculated based on the diabatic states constructed by the constrained density functional theory.The fluctuation of the electronic coupling is further revealed by molecular dynamics simulation.Succeedingly,the diagonal and off-diagonal fluctuations of thc Hamiltonian are mapped from the correlation functions of those parameters,and the rate is then estimated both from the perturbation theory and wavepacket diffusion method.The results manifest that both the static and dynamic fluctuations enhance the rate significantly,but the rate from the dynamic fluctuation is smaller than that from the static fluctuation.

  2. Cloning, characterization, and properties of seven triplet repeat DNA sequences. (United States)

    Ohshima, K; Kang, S; Larson, J E; Wells, R D


    Several neuromuscular and neurodegenerative diseases are caused by genetically unstable triplet repeat sequences (CTG.CAG, CGG.CCG, or AAG.CTT) in or near the responsible genes. We implemented novel cloning strategies with chemically synthesized oligonucleotides to clone seven of the triplet repeat sequences (GTA.TAC, GAT.ATC, GTT.AAC, CAC.GTG, AGG.CCT, TCG.CGA, and AAG.CTT), and the adjoining paper (Ohshima, K., Kang, S., Larson, J. E., and Wells, R. D.(1996) J. Biol. Chem. 271, 16784-16791) describes studies on TTA.TAA. This approach in conjunction with in vivo expansion studies in Escherichia coli enabled the preparation of at least 81 plasmids containing the repeat sequences with lengths of approximately 16 up to 158 triplets in both orientations with varying extents of polymorphisms. The inserts were characterized by DNA sequencing as well as DNA polymerase pausings, two-dimensional agarose gel electrophoresis, and chemical probe analyses to evaluate the capacity to adopt negative supercoil induced non-B DNA conformations. AAG.CTT and AGG.CCT form intramolecular triplexes, and the other five repeat sequences do not form any previously characterized non-B structures. However, long tracts of TCG.CGA showed strong inhibition of DNA synthesis at specific loci in the repeats as seen in the cases of CTG.CAG and CGG.CCG (Kang, S., Ohshima, K., Shimizu, M., Amirhaeri, S., and Wells, R. D.(1995) J. Biol. Chem. 270, 27014-27021). This work along with other studies (Wells, R. D.(1996) J. Biol. Chem. 271, 2875-2878) on CTG.CAG, CGG.CCG, and TTA.TAA makes available long inserts of all 10 triplet repeat sequences for a variety of physical, molecular biological, genetic, and medical investigations. A model to explain the reduction in mRNA abundance in Friedreich's ataxia based on intermolecular triplex formation is proposed.

  3. Updated scalar sector constraints in Higgs triplet model

    CERN Document Server

    Das, Dipankar


    We show that in the Higgs triplet model, after the Higgs discovery, the mixing angle in the CP-even sector can be strongly constrained from unitarity. We also discuss how large quantum effects in $h\\to\\gamma\\gamma$ may arise in a SM-like scenario and a certain part of the parameter space can be ruled out from the diphoton signal strength. Using $T$-parameter and diphoton signal strength measurements, we update the bounds on the nonstandard scalar masses.

  4. Polaron pair mediated triplet generation in polymer/fullerene blends

    KAUST Repository

    Dimitrov, Stoichko D.


    Electron spin is a key consideration for the function of organic semiconductors in light-emitting diodes and solar cells, as well as spintronic applications relying on organic magnetoresistance. A mechanism for triplet excited state generation in such systems is by recombination of electron-hole pairs. However, the exact charge recombination mechanism, whether geminate or nongeminate and whether it involves spin-state mixing is not well understood. In this work, the dynamics of free charge separation competing with recombination to polymer triplet states is studied in two closely related polymer-fullerene blends with differing polymer fluorination and photovoltaic performance. Using time-resolved laser spectroscopic techniques and quantum chemical calculations, we show that lower charge separation in the fluorinated system is associated with the formation of bound electron-hole pairs, which undergo spin-state mixing on the nanosecond timescale and subsequent geminate recombination to triplet excitons. We find that these bound electron-hole pairs can be dissociated by electric fields.

  5. Triplet Energy Transport in Platinum-Acetylide Light Harvesting Arrays. (United States)

    Chen, Zhuo; Hsu, Hsien-Yi; Arca, Mert; Schanze, Kirk S


    Light harvesting and triplet energy transport is investigated in chromophore-functionalized polystyrene polymers featuring light harvesting and energy acceptor chromophores (traps) at varying loading. The series of precision polymers was constructed via reversible addition-fragmentation transfer polymerization and functionalized with platinum acetylide triplet chromophores by using an azide-alkyne "click" reaction. The polymers have narrow polydispersity and degree of polymerization ∼60. The chromophores have the general structure, trans-[-R-C6H4-C≡C-Pt(PBu3)2-C≡C-Ar], where R is the attachment point to the polystyrene backbone and Ar is either -C6H4-C≡C-Ph or -pyrenyl (PE2-Pt and Py-Pt, respectively, with triplet energies of 2.35 and 1.88 eV). The polychromophores contain mainly the high-energy PE2-Pt units (light absorber and energy donor), with randomly distributed Py-Pt units (3-20% loading, energy acceptor). Photophysical methods are used to study the dynamics and efficiency of energy transport from the PE2-Pt to Py-Pt units in the polychromophores. The energy transfer efficiency is >90% for copolymers that contain 5% of the Py-Pt acceptor units. Time-resolved phosphorescence measurements combined with Monte Carlo exciton dynamics simulations suggest that the mechanism of exciton transport is exchange energy transfer hopping between PE2-Pt units.

  6. Analysis of Leptogenesis in Supersymmetric Triplet Seesaw Model

    CERN Document Server

    Chun, E J


    We analyze leptogenesis in a supersymmetric triplet seesaw scenario that explains the observed neutrino masses, adopting a phenomenological approach where the decay branching ratios of the triplets and the amount of CP--violation in its different decay channels are assumed as free parameters. We find that the solutions of the relevant Boltzmann equations lead to a rich phenomenology, in particular much more complex compared to the non--supersymmetric case, mainly due to the presence of an additional Higgs doublet. Several unexpected and counter--intuitive behaviors emerge from our analysis: the amount of CP violation in one of the decay channels can prove to be be irrelevant to the final lepton asymmetry, leading to successful leptogenesis even in scenarios with a vanishing CP violation in the leptonic sector; gauge annihilations can be the dominant effect in the determination of the evolution of the triplet density up to very high values of its mass, leading anyway to a sizeable final lepton asymmetry, which...

  7. Renormalization of the Higgs sector in the triplet model

    CERN Document Server

    Aoki, Mayumi; Kikuchi, Mariko; Yagyu, Kei


    We study radiative corrections to the mass spectrum and the triple Higgs boson coupling in the model with an additional Y=1 triplet field. In this model, the vacuum expectation value for the triplet field is strongly constrained from the electroweak precision data, under which characteristic mass spectrum appear at the tree level; i.e., $m_{H^{++}}^2-m_{H^+}^2\\simeq m_{H^+}^2-m_A^2$ and $m_A^2\\simeq m_H^2$, where the CP-even ($H$), the CP-odd ($A$) and the doubly-charged ($H^{\\pm\\pm}$) as well as the singly-charged ($H^\\pm$) Higgs bosons are the triplet-like. We evaluate how the tree-level formulae are modified at the one-loop level. The $hhh$ coupling for the standard model-like Higgs boson ($h$) is also calculated at the one-loop level. One-loop corrections to these quantities can be large enough for identification of the model by future precision data at the LHC or the International Linear Collider.

  8. Renormalization of the Higgs sector in the triplet model

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Mayumi [Institute for Theoretical Physics, Kanazawa University, Kanazawa 920-1192 (Japan); Kanemura, Shinya; Kikuchi, Mariko [Department of Physics, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Yagyu, Kei, E-mail: [Department of Physics, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); National Central University, Physics and Center for Mathematics and Theoretical Physics, No. 300, Jhongda Rd., Jhongli, Taiwan (China)


    We study radiative corrections to the mass spectrum and the triple Higgs boson coupling in the model with an additional Y=1 triplet field. In this model, the vacuum expectation value for the triplet field is strongly constrained from the electroweak precision data, under which characteristic mass spectrum appear at the tree level; i.e., m{sub H{sup +}{sup +2}}-m{sub H{sup +2}} Asymptotically-Equal-To m{sub H{sup +2}}-m{sub A}{sup 2} and m{sub A}{sup 2} Asymptotically-Equal-To m{sub H}{sup 2}, where the CP-even (H), the CP-odd (A) and the doubly-charged (H{sup {+-}{+-}}) as well as the singly-charged (H{sup {+-}}) Higgs bosons are the triplet-like. We evaluate how the tree-level formulae are modified at the one-loop level. The hhh coupling for the standard model-like Higgs boson (h) is also calculated at the one-loop level. One-loop corrections to these quantities can be large enough for identification of the model by future precision data at the LHC or the International Linear Collider.

  9. Encapsulated triplet-triplet annihilation-based upconversion in the aqueous phase for sub-band-gap semiconductor photocatalysis. (United States)

    Kim, Jae-Hyuk; Kim, Jae-Hong


    We herein report the first instance of aqueous-phase photosensitization of semiconductor photocatalysts (WO(3) loaded with Pt) through triplet-triplet annihilation (TTA)-based upconversion of sub-band-gap photons. The TTA-based upconversion (UC) was achieved in the aqueous phase by encapsulating the solvent phase containing a benchmark platinum(II) octaethylporphyrin/9,10-diphenylanthracene sensitizer/acceptor pair in a rigid polymer shell in the form of aqueous dispersible microcapsules. A mixture of hexadecane and polyisobutylene was used as the inner solvent phase. This eliminated the need for the deoxygenation step that is essential for existing TTA-based UC processes and enabled stable UC to occur even after a month of exposure to the ambient environment. The photoluminescence properties were examined, and UC-assisted photochemical production of hydroxyl radical from green (532 nm) light irradiation was demonstrated for the first time.

  10. Entanglement and Metrology with Singlet-Triplet Qubits (United States)

    Shulman, Michael Dean

    Electron spins confined in semiconductor quantum dots are emerging as a promising system to study quantum information science and to perform sensitive metrology. Their weak interaction with the environment leads to long coherence times and robust storage for quantum information, and the intrinsic tunability of semiconductors allows for controllable operations, initialization, and readout of their quantum state. These spin qubits are also promising candidates for the building block for a scalable quantum information processor due to their prospects for scalability and miniaturization. However, several obstacles limit the performance of quantum information experiments in these systems. For example, the weak coupling to the environment makes inter-qubit operations challenging, and a fluctuating nuclear magnetic field limits the performance of single-qubit operations. The focus of this thesis will be several experiments which address some of the outstanding problems in semiconductor spin qubits, in particular, singlet-triplet (S-T0) qubits. We use these qubits to probe both the electric field and magnetic field noise that limit the performance of these qubits. The magnetic noise bath is probed with high bandwidth and precision using novel techniques borrowed from the field of Hamiltonian learning, which are effective due to the rapid control and readout available in S-T 0 qubits. These findings allow us to effectively undo the undesired effects of the fluctuating nuclear magnetic field by tracking them in real-time, and we demonstrate a 30-fold improvement in the coherence time T2*. We probe the voltage noise environment of the qubit using coherent qubit oscillations, which is partially enabled by control of the nuclear magnetic field. We find that the voltage noise bath is frequency-dependent, even at frequencies as high as 1MHz, and it shows surprising and, as of yet, unexplained temperature dependence. We leverage this knowledge of the voltage noise environment, the

  11. Mixed Inert Scalar Triplet Dark Matter, Radiative Neutrino Masses and Leptogenesis

    CERN Document Server

    Lu, Wen-Bin


    The neutral component of an inert scalar multiplet with hypercharge can provide a stable dark matter particle when its real and imaginary parts have a splitting mass spectrum. Otherwise, a tree-level dark matter-nucleon scattering mediated by the $Z$ boson will be much above the experimental limit. In this paper we focus on a mixed inert scalar triplet dark matter scenario where a complex scalar triplet with hypercharge can mix with another real scalar triplet without hypercharge through their renormalizable coupling to the standard model Higgs doublet. We consider three specified cases that carry most of the relevant features of the full parameter space: (i) the neutral component of the real triplet dominates the dark matter particle, (ii) the neutral component of the complex triplet dominates the dark matter particle; and (iii) the neutral components of the real and complex triplets equally constitute the dark matter particle. Subject to the dark matter relic abundance and direct detection constraint, we pe...

  12. Enhancing triplet superconductivity by the proximity to a singlet superconductor in oxide heterostructures (United States)

    Horsdal, Mats; Khaliullin, Giniyat; Hyart, Timo; Rosenow, Bernd


    We show how in principle a coherent coupling between two superconductors of opposite parity can be realized in a three-layer oxide heterostructure. Due to strong intraionic spin-orbit coupling in the middle layer, singlet Cooper pairs are converted into triplet ones and vice versa. This results in a large enhancement of the triplet superconductivity, persisting well above the native triplet critical temperature.

  13. Capturing triplet emission in white organic light emitting devices

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Jai [Faculty of EHSE, School of Engineering and IT, B-purple-12, Charles Darwin University, Darwin, NT 0909 (Australia)


    The state-of-the art in the white organic light emitting devices (WOLEDs) is reviewed for further developments with a view to enhance the capture of triplet emission. In particular, applying the new exciton-spin-orbit-photon interaction operator as a perturbation, rates of spontaneous emission are calculated in a few phosphorescent materials and compared with experimental results. For iridium based phosphorescent materials the rates agree quite well with the experimental results. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Status of the LHC inner triplet quadrupole program at Fermilab

    CERN Document Server

    Andreev, N; Bauer, P; Bossert, R; Brandt, J; Carson, J; Caspi, S; Chichili, D R; Chiesa, L; Darve, C; Di Marco, J; Fehér, S; Ghosh, A; Glass, H; Huang, Y; Kerby, J S; Lamm, M J; Markarov, A A; McInturff, A D; Nicol, T H; Nobrega, A; Novitski, I; Ogitsu, T; Orris, D; Ozelis, J P; Page, T; Peterson, T; Rabehl, Roger Jon; Robotham, W; Sabbi, G L; Scanlan, R M; Schlabach, P; Sylvester, C D; Strait, J B; Tartaglia, M; Tompkins, J C; Velev, G V; Yadav, S; Zlobin, A V


    Fermilab, in collaboration with LBNL and BNL, is developing a quadrupole for installation in the interaction region inner triplets of the LHC. This magnet is required to have an operating gradient of 215 T/m across a 70 mm coil bore, and operates in superfluid helium at 1.9 K. A 2 m magnet program addressing mechanical, magnetic, quench protection, and thermal issues associated with the design was completed earlier this year, and production of the first full length, cryostatted prototype magnet is underway. This paper summarizes the conclusions of the 2 m program, and the design and status of the first full-length prototype magnet. (11 refs).

  15. Tunneling Conductance in Normal Metal/Insulator/Triplet Superconductor Junction

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Wei


    Tunneling conductance in normal metal/insulator/triplet superconductor junctions is studied theoretically as a function of the bias voltage at zero temperature and finite temperature. The results show there are zero-bias conductance peak, zero-bias conductance dip and double-minimum structures in the spectra for p-wave superconductor junctions. The existence of such structures in the conductance spectrum can be taken as evidence that the pairing symmetry of Sr2RuO4 is p-wave symmetry.

  16. String theory triplets and higher-spin curvatures

    CERN Document Server

    Francia, Dario


    Unconstrained local Lagrangians for higher-spin gauge theories are bound to involve auxiliary fields, whose integration in the partition function generates geometric, effective actions expressed in terms of curvatures. When applied to the triplets, emerging from the tensionless limit of open string field theory, the same procedure yields interesting alternative forms of geometric Lagrangians, whose rather simple pattern is essentially the same for bosons and fermions. This shows that higher-spin curvatures might play a role in the dynamics, regardless of whether the Fronsdal-Labastida constraints are assumed or not.

  17. String theory triplets and higher-spin curvatures

    Energy Technology Data Exchange (ETDEWEB)

    Francia, Dario, E-mail: francia@apc.univ-paris7.f [AstroParticule et Cosmologie (APC), Universite Paris VII - Campus Paris Rive Gauche, 10, rue Alice Domon et Leonie Duquet, F-75205 Paris Cedex 13 (France)


    Unconstrained local Lagrangians for higher-spin gauge theories are bound to involve auxiliary fields, whose integration in the partition function generates geometric, effective actions expressed in terms of curvatures. When applied to the triplets, emerging from the tensionless limit of open string field theory, the same procedure yields interesting alternative forms of geometric Lagrangians, expressible for both bosons and fermions as squares of field-strengths. This shows that higher-spin curvatures might play a role in the dynamics, regardless of whether the Fronsdal-Labastida constraints are assumed or forgone.

  18. Mother-daughter in vitro fertilization triplet surrogate pregnancy. (United States)

    Michelow, M C; Bernstein, J; Jacobson, M J; McLoughlin, J L; Rubenstein, D; Hacking, A I; Preddy, S; Van der Wat, I J


    A successful triplet pregnancy has been established in a surrogate gestational mother following the transfer of five embryos fertilized in vitro. The oocytes were donated by her biological daughter, and the sperm obtained from the daughter's husband. The daughter's infertility followed a total abdominal hysterectomy performed for a postpartum hemorrhage as a result of a placenta accreta. Synchronization of both their menstrual cycles was obtained using oral contraceptive suppression for 2 months, followed by stimulation of both the surrogate gestational mother and her daughter such that embryo transfer would occur at least 48 hr after the surrogate gestational mother's own ovulation. This case raises a number of medical, social, psychological, and ethical issues.

  19. Immobilization of Fusarium verticillioides fungus on nano-silica (NSi-Fus): a novel and efficient biosorbent for water treatment and solid phase extraction of Mg(II) and Ca(II). (United States)

    Mahmoud, Mohamed E; Yakout, Amr A; Abdel-Aal, Hany; Osman, Maher M


    Biosorption and water treatment of Mg(II) and Ca(II) hardness was designed via surface loading of heat inactivated Fusarium verticillioides fungus (Fus) on nano-silica (NSi) for developing the (NSi-Fus) as a novel biosorbent. Surface characterization was confirmed by FT-IR and SEM analysis. The (NSi), (Fus) and (NSi-Fus) sorbents were investigated for removal of Mg(II) and Ca(II) by using the batch equilibrium technique under the influence of solution pH, contact time, sorbent dosage, initial metal concentration and interfering ion. The maximum magnesium capacity values were identified as 600.0, 933.3 and 1000.0 μmole g(-1) while, the maximum calcium values were 1066.7, 1800.0 and 1333.3 μmole g(-1) for (NSi), (Fus) and (NSi-Fus), respectively. Sorption equilibria were established in ∼20 min and the data were well described by both Langmuir and Freundlich models. The potential applications of these biosorbents for water-softening and extraction of magnesium and calcium from sea water samples were successfully accomplished.

  20. Laser-induced atomic fragment fluorescence spectroscopy: a facile technique for molecular spectroscopy of spin-forbidden states. (United States)

    Zhang, Qun; Chen, Yang; Keil, Mark


    Spectra of spin-forbidden and spin-allowed transitions in the mixed b (3)Pi(u) approximately A (1)Sigma(u)(+) state of Na(2) are measured separately by two-photon excitation using a single tunable dye laser. The two-photon excitation produces Na(*)(3p) by photodissociation, which is easily and sensitively detected by atomic fluorescence. At low laser power, only the A (1)Sigma(u)(+) state is excited, completely free of triplet excitation. At high laser power, photodissociation via the intermediate b (3)Pi(u) triplet state becomes much more likely, effectively "switching" the observations from singlet spectroscopy to triplet spectroscopy with only minor apparatus changes. This technique of perturbation-assisted laser-induced atomic fragment fluorescence may therefore be especially useful as a general vehicle for investigating perturbation-related physics pertinent to the spin-forbidden states, as well as for studying allowed and forbidden states of other molecules.

  1. Mode of conception of triplets and high order multiple pregnancies.

    LENUS (Irish Health Repository)

    Basit, I


    A retrospective audit was performed of all high order multiple pregnancies (HOMPs) delivered in three maternity hospitals in Dublin between 1999 and 2008. The mode of conception for each pregnancy was established with a view to determining means of reducing their incidence. A total of 101 HOMPs occurred, 93 triplet, 7 quadruplet and 1 quintuplet. Information regarding the mode of conception was available for 78 (81%) pregnancies. Twenty eight (27.7%) were spontaneous, 34 (33.7%) followedlVF\\/ICSI\\/FET treatment (in-vitro fertilisation, intracytoplasmic sperm injection, frozen embryo transfer), 16 (15.8%) resulted from Clomiphene Citrate treatment and 6 (6%) followed ovulation induction with gonadotrophins. Triplet and HOMPs are a major cause of maternal, feta land neonatal morbidity. Many are iatrogenic, arising from fertility treatments including Clomiphene. Reducing the numbers of embryos transferred will address IVF\\/ICSI\\/FET-related multiple pregnancy rates and this is currently happening in Ireland. Clomiphene and gonadotrophins should only be prescribed when appropriate resources are available to monitor patients adequately.

  2. Supersymmetric grand unification with light color-triplet (United States)

    Berezhiani, Lasha


    We construct a natural model of the supersymmetric SU (6) unification, in which the symmetry breaking, down to the standard model gauge group, results in the number of pseudo-Nambu-Goldstone superfields with interesting properties. Namely, besides the Higgs doublet-antidoublet pair which is responsible for the electroweak phase transition, the Nambu-Goldstone sector consists of multiplets in the anti- and fundamental representations of SU (5). While being strictly massless in the supersymmetric limit, they acquire the weak scale masses as a result of its breaking. The color-triplet components of this light sector could, in principle, mediate an unacceptably fast proton decay; however, because of the natural TeV /MGUT suppression of the Yukawa couplings to the light quarks and leptons, their existence is compatible with the experimental bound on proton lifetime. This suppression is made further interesting, since it results in the lifetime, of the lightest of the above-mentioned colored particles from 1 s to 1 day, long enough for it to appear stable in the detector. Furthermore, we argue that the accommodation of the color-triplet pseudo-Nambu-Goldstones, without fine-tuning or contradicting observations, implies SU (6) unification.

  3. Caught in the Act: Discovery of a Physical Quasar Triplet

    CERN Document Server

    Farina, E P; Decarli, R; Fumagalli, M


    We present the discovery of a triplet of quasars at z~1.51. The whole system is well accommodated within 25 arcsec (i.e., 200 kpc in projected distance). The velocity differences among the three objects (as measured through the broad MgII emission line) are less than 1000 km/s, suggesting that the quasars belong to the same physical structure. Broad band NIR images of the field do not reveal evidence of galaxies or galaxy clusters that could act as a gravitational lens, ruling out the possibility that two or all the three quasars are multiple images of a single, strongly lensed source. QQQ J1519+0627 is the second triplet of quasars known up to date. We estimate that these systems are extremely rare in terms of simple accidental superposition. The lack of strong galaxy overdensity suggests that this peculiar system is harboured in the seeds of a yet-to-be-formed massive structure. Based on observations collected at the La Silla Observatory with the New Technology Telescope (NTT) of the European Southern Obser...

  4. Reversible Photoisomerization among Triplet Amino Naphthylnitrene, Triplet Diimine Biradical, and Indazole: Matrix-Isolation IR Spectra of 8-Amino-1-naphthylnitrene, 1,8-Naphthalenediimine, and 1,2-Dihydrobenz[cd]indazole. (United States)

    Okamura, Takuya; Akai, Nobuyuki; Nakata, Munetaka


    Reaction mechanisms of nitrene, one of the most famous biradicals, have been frequently studied, and many spectral data have been obtained so far. In the present study, the experimental IR spectra of triplet 8-amino-1-naphthylnitrene ((3)ANN), a triplet diimine biradical 1,8-dihydro-1,8-naphthalenediimine ((3)DND), and 1,2-dihydrobenz[cd]indazole (DBI), which are produced in the UV photolysis of 1,8-diaminonaphthalene in an Ar matrix and identified by a combination method of IR spectroscopy and DFT quantum chemical calculations, are first reported. (3)ANN is found to change to DBI by hydrogen-atom migration with bond making between the two nitrogen atoms upon visible-light irradiation (λ > 580 nm) with its backward reaction caused by 350 nm irradiation. In addition, (3)ANN isomerizes to (3)DND by 700 nm irradiation, while its backward reaction occurs upon 500 nm irradiation. The wavelength dependences of these photoisomerizations are explained in terms of their electronic transition energies estimated by time-dependent DFT calculations. It is concluded that the novel reversible photoisomerization system among (3)ANN, (3)DND, and DBI is totally different from the well-known photoisomerization between phenylnitrene and a seven-membered cyclic compound.

  5. Excited triplet state photophysics of the sulphonated aluminium phthalocyanines bound to human serum albumin. (United States)

    Foley, M S; Beeby, A; Parker, A W; Bishop, S M; Phillips, D


    The binding of the sulphonated aluminum phthalocyanines to human serum albumin (HSA) in aqueous phosphate buffer solution at 25 degrees C has been studied by measuring the properties of the triplet excited states of these dyes. The triplet lifetimes were measured by triplet-triplet absorption flash photolysis. The triplet lifetime of the disulphonated AlS2Pc (2.5 microM) varies from 500 +/- 30 microseconds in the absence of protein to 1.100 microseconds and longer with HSA concentrations above 100 microM. Under identical conditions, the maximum triplet lifetimes of the mono-, tri- and tetrasulphonated compounds bound to HSA are shorter than those for the disulphonated species. The increase in the triplet state lifetimes is attributed to the ability of the bulk aqueous phase to interact with the sensitizer at the site of binding; the site of binding being dependent on the degree of sulphonation. For AlS2Pc and AlS3Pc at all HSA concentrations, and regardless of the degree of sulphonation, all the triplet state decay profiles follow simple pseudo-first-order kinetics. The exponential decay of the triplet phthalocyanine at all HSA concentrations is ascribed to the rapid association and dissociation of the phthalocyanine-HSA complex on the time-scales of the triplet state lifetimes. A simplified one-step binding model is utilized to describe the results. The association of AlS1Pc with HSA results in substantial quenching of the triplet state quantum yield, and a more complex model is required to analyze the results. The tetrasulphonated compound (AlS4Pc) binds to the protein at a site where it experiences some protection from the aqueous phase.

  6. Using the Ca II Triplet to Trace Abundance Variations in Individual Red Giant Branch stars in Three Nearby Galaxies

    CERN Document Server

    Tolstoy, E; Cole, A A; Pasquini, L; Gilmozzi, R; Gallagher, J S; Tolstoy, Eline; Irwin, Michael J.; Cole, Andrew A.


    Spectroscopic abundance determinations for stars spanning a Hubble time in age are necessary in order to unambiguously determine the evolutionary histories of galaxies. Using FORS1 in Multi-Object Spectroscopy mode on ANTU (UT1) at the ESO-VLT on Paranal we obtained near infrared spectra from which we measured the equivalent widths of the two strongest Ca II triplet lines to determine metal abundances for a sample of Red Giant Branch stars, selected from ESO-NTT optical (I, V-I) photometry of three nearby, Local Group, galaxies: the Sculptor Dwarf Spheroidal, the Fornax Dwarf Spheroidal and the Dwarf Irregular NGC 6822. The summed equivalent width of the two strongest lines in the Ca II triplet absorption line feature, centered at 8500A, can be readily converted into an [Fe/H] abundance using the previously established calibrations by Armandroff & Da Costa (1991) and Rutledge, Hesser & Stetson (1997). We measured metallicities for 37 stars in Sculptor, 32 stars in Fornax, and 23 stars in NGC 6822, yie...

  7. Triplet-triplet annihilation upconversion in CdS-decorated SiO2 nanocapsules for sub-bandgap photocatalysis. (United States)

    Kwon, Oh Seok; Kim, Jae-Hyuk; Cho, Jin Ku; Kim, Jae-Hong


    This study reports the first successful nanoscale encapsulation of triplet-triplet annihilation upconversion (TTA-UC) medium within a rigid silica shell using a self-assembly microemulsion process. These newly synthesized nanocapsules present a few critical advances that could be instrumental for a wide range of aqueous-based photonics applications, including photocatalysis, artificial photosynthesis, and bioimaging. The nanocapsules form a homogeneous suspension that can produce intense, diffuse UC emission in water without deoxygenation, closely resembling conventional TTA-UC processes that have been performed in deoxygenated organic solvents. The silica shell provides sites for further surface modification, which allows, when combined with its nanoscale dimension and structural rigidity, this TTA-UC system to acquire various useful functionalities. A benchmark TTA-UC pair, palladium(II) tetraphenyltetrabenzoporphyrin as a sensitizer and perylene as an acceptor, was used to demonstrate efficient red-to-blue (635 nm, 1.95 eV → 470 nm, 2.6 eV) upconversion in the oxygen-rich aqueous phase. The nanocapsule surface was further functionalized with cadmium sulfide nanoparticles (Eg = 2.4 eV) to demonstrate sub-bandgap sensitization and subsequent aqueous-phase catalytic oxidation.

  8. Spectroscopic evidence for triplet excitation energy transfer among carotenoids in the LH2 complex from photosynthetic bacterium Rhodopseudomonas palustris

    Institute of Scientific and Technical Information of China (English)

    FENG Juan; WANG Qian; ZHANG Xujia; HUANG Youguo; AI Xicheng; ZHANG Xingkang; ZHANG Jianping


    The LH2 complex from Rhodopsudomonas (Rps.) palustris is unique in the heterogeneous carotenoid compositions. The dynamics of triplet excited state Carotenoids (3Car*) has been investigated by means of sub-microsecond time-resolved absorption spectroscopy both at physiological temperature (295 K) and at cryogenic temperature (77 K). Broad and asymmetric Tn←T1 transient absorption was observed at room temperature following the photo-excitation of Car at 532 nm, which suggests the contribution from various carotenoid compositions having different numbers of conjugated C=C double bonds (NC=C). The triplet absorption bands of different carotenoids, which superimposed at room temperature, could be clearly distinguished upon decreasing the temperature down to 77 K. At room temperature the shorter-wavelength side of the main Tn←T1 absorption band decayed rapidly to reach a spectral equilibration with a characteristic time constant of~1 μs, the same spectral dynamics, however, was not observed at 77 K. The aforementioned spectral dynamics can be explained in terms of the triplet-excitation transfer among heterogeneous carotenoid compositions. Global spectral analysis was applied to the time-resolved spectra at room temperature, which revealed two spectral components peaked at 545 and 565 nm, and assignable to the Tn←T1 absorption of Cars with NC=C=11 and NC=C=13, respectively. Surprisingly, the decay time constant of a shorter-con- jugated Car, I.e. 0.72 μs (aerobic) and 1.36 μs (anaerobic), is smaller than that of a longer-con- jugated Car, I.e. 2.12 μs (aerobic) and 3.75 μs (anaerobic), which is contradictory to the general rule of carotenoids and relative polyenes. The results are explained in terms of triplet-excitation transfer among different types of Cars. It is postulated that two Cars with different conjugation lengths coexist in an α,β-subunit in the LH2 complex.

  9. Resonance raman and absorption spectra of isomeric retinals in their lowest excited triplet states

    DEFF Research Database (Denmark)

    Wilbrandt, Robert Walter; Jensen, N.-H.; Houee-Levin, C.


    implications about the size of the energy barriers separating the various triplet species are discussed. The resonance Raman spectra obtained by using either anthracene (ET = 177.7 kJ mol-1) or naphthalene (ET = 254.8 kJ mol-1) as sensitizers were virtually identical for the corresponding triplet states from...

  10. Direct Measurement of the Triplet Exciton Diffusion Length in Organic Semiconductors

    NARCIS (Netherlands)

    Mikhnenko, Oleksandr V.; Ruiter, Roald; Blom, Paul W. M.; Loi, Maria Antonietta


    We present a new method to measure the triplet exciton diffusion length in organic semiconductors. N,N'-di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl-4,4'-diamine (NPD) has been used as a model system. Triplet excitons are injected into a thin film of NPD by a phosphorescent thin film, which is opti

  11. Triangle Type Trinuclear Copper Complexes with Triplet -excitation Luminescent Property, an Ab Initio Study

    Institute of Scientific and Technical Information of China (English)

    MANG Chao-Yong; ZHANG Ming-Xin; WU Ke-Chen


    The luminescent mechanism and properties of a triangular Cu(I) complex, (CuPz)3, have been studied by CIS method. The ground and lowest triplet excitation state geometries were optimized at MP2/SBKJC and CIS/SBKJC levels, respectively. A remarkable geometry distortion of the lowest triplet state was found and believed to cause the emission spectra to red shift.

  12. TripNet: A Heuristic Algorithm for Constructing Rooted Phylogenetic Networks from Triplets

    CERN Document Server

    Poormohammadi, Hadi; Tusserkani, Ruzbeh


    The problem of constructing an optimal rooted phylogenetic network from a set of rooted triplets is an NP-hard problem. In this paper, we present a heuristic algorithm called TripNet which tries to construct an optimal rooted phylogenetic network from an arbitrary set of triplets. We prove some theorems to justify the performance of the algorithm.

  13. GAA triplet-repeats cause nucleosome depletion in the human genome. (United States)

    Zhao, Hongyu; Xing, Yongqiang; Liu, Guoqing; Chen, Ping; Zhao, Xiujuan; Li, Guohong; Cai, Lu


    Although there have been many investigations into how trinucleotide repeats affect nucleosome formation and local chromatin structure, the nucleosome positioning of GAA triplet-repeats in the human genome has remained elusive. In this work, the nucleosome occupancy around GAA triplet-repeats across the human genome was computed statistically. The results showed a nucleosome-depleted region in the vicinity of GAA triplet-repeats in activated and resting CD4(+) T cells. Furthermore, the A-tract was frequently adjacent to the upstream region of GAA triplet-repeats and could enhance the depletion surrounding GAA triplet-repeats. In vitro chromatin reconstitution assays with GAA-containing plasmids also demonstrated that the inserted GAA triplet-repeats destabilized the ability of recombinant plasmids to assemble nucleosomes. Our results suggested that GAA triplet-repeats have lower affinity to histones and can change local nucleosome positioning. These findings may be helpful for understanding the mechanism of Friedreich's ataxia, which is associated with GAA triplet-repeats at the chromatin level.

  14. Instability of human TATA-binding protein CAG triplet repeats during amplification by PCR. (United States)

    Holstege, F C; van der Vliet, P C; Timmers, H T


    Polymerase chain reaction (PCR) of a TATA-binding protein cDNA that contains CAG triplet repeats results in heterogeneous products. This is caused by a variable loss in the number of CAG triplets. Sequence analysis of PCR products suggests that instability increases with repeat length.

  15. Two Birds with One Stone: Tailoring Singlet Fission for Both Triplet Yield and Exciton Diffusion Length

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Tong [Department of Chemistry, Purdue University, West Lafayette IN 47907 USA; Wan, Yan [Department of Chemistry, Purdue University, West Lafayette IN 47907 USA; Guo, Zhi [Department of Chemistry, Purdue University, West Lafayette IN 47907 USA; Johnson, Justin [National Renewable Energy Laboratory, 15013 Denver West Pkwy Golden CO 80401 USA; Huang, Libai [Department of Chemistry, Purdue University, West Lafayette IN 47907 USA


    By direct imaging of singlet and triplet populations with ultrafast microscopy, it is shown that the triplet diffusion length and singlet fission yield can be simultaneously optimized for tetracene and its derivatives, making them ideal structures for application in bilayer solar cells.

  16. Codon-triplet context unveils unique features of the Candida albicans protein coding genome

    Directory of Open Access Journals (Sweden)

    Oliveira José L


    Full Text Available Abstract Background The evolutionary forces that determine the arrangement of synonymous codons within open reading frames and fine tune mRNA translation efficiency are not yet understood. In order to tackle this question we have carried out a large scale study of codon-triplet contexts in 11 fungal species to unravel associations or relationships between codons present at the ribosome A-, P- and E-sites during each decoding cycle. Results Our analysis unveiled high bias within the context of codon-triplets, in particular strong preference for triplets of identical codons. We have also identified a surprisingly large number of codon-triplet combinations that vanished from fungal ORFeomes. Candida albicans exacerbated these features, showed an unbalanced tRNA population for decoding its pool of codons and used near-cognate decoding for a large set of codons, suggesting that unique evolutionary forces shaped the evolution of its ORFeome. Conclusion We have developed bioinformatics tools for large-scale analysis of codon-triplet contexts. These algorithms identified codon-triplets context biases, allowed for large scale comparative codon-triplet analysis, and identified rules governing codon-triplet context. They could also detect alterations to the standard genetic code.

  17. Generalization of the possible algebraic basis of q-triplets (United States)

    Tsallis, Constantino


    The so called q-triplets were conjectured in 2004 [C. Tsallis, Physica A 340, 1 (2004)] and then found in nature in 2005 [L.F. Burlaga, A.F. Vinas, Physica A 356, 375 (2005)]. A relevant further step was achieved in 2005 [C. Tsallis, M. Gell-Mann, Y. Sato, PNAS 102, 15377 (2005)] when the possibility was advanced that they could reflect an entire infinite algebra based on combinations of the self-dual relations q → 2 - q (additive duality) and q → 1/q (multiplicative duality). The entire algebra collapses into the single fixed point q = 1, corresponding to the Boltzmann-Gibbs entropy and statistical mechanics. For q ≠ 1, an infinite set of indices q appears, corresponding in principle to an infinite number of physical properties of a given complex system describable in terms of the so called q-statistics. The basic idea that is put forward is that, for a given universality class of systems, a small number (typically one or two) of independent q indices exist, the infinite others being obtained from these few ones by simply using the relations of the algebra. The q-triplets appear to constitute a few central elements of the algebra. During the last decade, an impressive amount of q-triplets have been exhibited in analytical, computational, experimental and observational results in natural, artificial and social systems. Some of them do satisfy the available algebra constructed solely with the additive and multiplicative dualities, but some others seem to violate it. In the present work we generalize those two dualities with the hope that a wider set of systems can be handled within. The basis of the generalization is given by the selfdual relation q → qa(q) ≡ ((a+2)-aq) / (a-(a-2)q) (a ∈ R). We verify that qa(1) = 1, and that q2(q) = 2 - q and q0(q) = 1/q. To physically motivate this generalization, we briefly review illustrative applications of q-statistics, in order to exhibit possible candidates where the present generalized algebras could be useful.

  18. Triplet-singlet conversion in ultracold Cs$_2$ and production of ground state molecules

    CERN Document Server

    Bouloufa, Nadia; Aymar, Mireille; Dulieu, Olivier


    We propose a process to convert ultracold metastable Cs$_2$ molecules in their lowest triplet state into (singlet) ground state molecules in their lowest vibrational levels. Molecules are first pumped into an excited triplet state, and the triplet-singlet conversion is facilitated by a two-step spontaneous decay through the coupled $A^{1}\\Sigma_{u}^{+} \\sim b ^{3}\\Pi_{u}$ states. Using spectroscopic data and accurate quantum chemistry calculations for Cs$_2$ potential curves and transition dipole moments, we show that this process has a high rate and competes favorably with the single-photon decay back to the lowest triplet state. In addition, we demonstrate that this conversion process represents a loss channel for vibrational cooling of metastable triplet molecules, preventing an efficient optical pumping cycle down to low vibrational levels.

  19. Supersymmetric Grand Unification with Light Color-Triplet

    CERN Document Server

    Berezhiani, Lasha


    We construct a natural model of the supersymmetric SU(6) unification, in which the symmetry breaking, down to the standard model gauge group, results in the number of pseudo-Nambu-Goldstone superfields with interesting properties. Namely, besides the Higgs doublet-antidoublet pair which is responsible for the electroweak phase transition, the Nambu-Goldstone sector consists of multiplets in the anti- and fundamental representations of SU(5). While being strictly massless in the supersymmetric limit, they acquire the weak scale masses as a result of its breaking. The color-triplet components of this light sector could, in principle, mediate an unacceptably fast proton decay; however, because of the natural $\\text{TeV}/M_{\\text{GUT}}$ suppression of the Yukawa couplings to the light quarks and leptons, their existence is compatible with the experimental bound on proton lifetime. This suppression is made further interesting, since it results in the lifetime, of the lightest of the above-mentioned colored particl...

  20. Model for Triplet State Engineering in Organic Light Emitting Diodes

    CERN Document Server

    Prodhan, Suryoday; Ramasesha, S


    Engineering the position of the lowest triplet state (T1) relative to the first excited singlet state (S1) is of great importance in improving the efficiencies of organic light emitting diodes and organic photovoltaic cells. We have carried out model exact calculations of substituted polyene chains to understand the factors that affect the energy gap between S1 and T1. The factors studied are backbone dimerisation, different donor-acceptor substitutions and twisted geometry. The largest system studied is an eighteen carbon polyene which spans a Hilbert space of about 991 million. We show that for reverse intersystem crossing (RISC) process, the best system involves substituting all carbon sites on one half of the polyene with donors and the other half with acceptors.

  1. Demonstration of entanglement of electrostatically coupled singlet-triplet qubits. (United States)

    Shulman, M D; Dial, O E; Harvey, S P; Bluhm, H; Umansky, V; Yacoby, A


    Quantum computers have the potential to solve certain problems faster than classical computers. To exploit their power, it is necessary to perform interqubit operations and generate entangled states. Spin qubits are a promising candidate for implementing a quantum processor because of their potential for scalability and miniaturization. However, their weak interactions with the environment, which lead to their long coherence times, make interqubit operations challenging. We performed a controlled two-qubit operation between singlet-triplet qubits using a dynamically decoupled sequence that maintains the two-qubit coupling while decoupling each qubit from its fluctuating environment. Using state tomography, we measured the full density matrix of the system and determined the concurrence and the fidelity of the generated state, providing proof of entanglement.

  2. Metrics for phylogenetic networks II: nodal and triplets metrics. (United States)

    Cardona, Gabriel; Llabrés, Mercè; Rosselló, Francesc; Valiente, Gabriel


    The assessment of phylogenetic network reconstruction methods requires the ability to compare phylogenetic networks. This is the second in a series of papers devoted to the analysis and comparison of metrics for tree-child time consistent phylogenetic networks on the same set of taxa. In this paper, we generalize to phylogenetic networks two metrics that have already been introduced in the literature for phylogenetic trees: the nodal distance and the triplets distance. We prove that they are metrics on any class of tree-child time consistent phylogenetic networks on the same set of taxa, as well as some basic properties for them. To prove these results, we introduce a reduction/expansion procedure that can be used not only to establish properties of tree-child time consistent phylogenetic networks by induction, but also to generate all tree-child time consistent phylogenetic networks with a given number of leaves.

  3. Spectroscopic (FT-IR, FT-Raman, 1H, 13C NMR, UV/VIS), thermogravimetric and antimicrobial studies of Ca(II), Mn(II), Cu(II), Zn(II) and Cd(II) complexes of ferulic acid (United States)

    Kalinowska, M.; Piekut, J.; Bruss, A.; Follet, C.; Sienkiewicz-Gromiuk, J.; Świsłocka, R.; Rzączyńska, Z.; Lewandowski, W.


    The molecular structure of Mn(II), Cu(II), Zn(II), Cd(II) and Ca(II) ferulates (4-hydroxy-3-methoxycinnamates) was studied. The selected metal ferulates were synthesized. Their composition was established by means of elementary and thermogravimetric analysis. The following spectroscopic methods were used: infrared (FT-IR), Raman (FT-Raman), nuclear magnetic resonance (13C, 1H NMR) and ultraviolet-visible (UV/VIS). On the basis of obtained results the electronic charge distribution in studied metal complexes in comparison with ferulic acid molecule was discussed. The microbiological study of ferulic acid and ferulates toward Escherichia coli, Bacillus subtilis, Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris was done.

  4. Synthesis, spectroscopic and thermal studies of Mg(II), Ca(II), Sr(II) and Ba(II) diclofenac sodium complexes as anti-inflammatory drug and their protective effects on renal functions impairment and oxidative stress. (United States)

    El-Megharbel, Samy M; Hamza, Reham Z; Refat, Moamen S


    The main task of our present study is the preparation of newly complexes of Mg(II), Ca(II), Sr(II) and Ba(II) with diclofenac which succeeded to great extent in alleviating the side effects of diclofenac alone and ameliorating the kidney function parameters and antioxidant capacities with respect to diclofenac treated group alone. The Mg(II), Ca(II), Sr(II) and Ba(II) with diclofenac have been synthesized and characterized using infrared, electronic and (1)H NMR spectral, thermogravimetric and conductivity measurements. The diclofenac ligand has been found to act as bidentate chelating agent. Diclofenac complexes coordinate through the oxygen's of the carboxyl group. The molar ratio chelation is 1:2 (M(2+)-dic) with general formula [M(dic)2(H2O)2]⋅nH2O. Antibacterial screening of the alkaline earth metal complexes against Escherichia coli (Gram-ve), Bacillus subtilis (Gram+ve) and anti-fungal (Asperagillus oryzae, Asperagillus niger, Asperagillus flavus) were investigated. The kidney functions in male albino rats were ameliorated upon treatment with metal complexes of dic, which are represented by decreasing the levels of urea and uric acid to be located within normal values. The other looks bright spot in this article is the assessment of antioxidant defense system including SOD, CAT and MDA with the help of Sr(2+), Mg(2+) and Ca(2+)-dic complexes. The hormones related to kidney functions and stresses have been greatly ameliorated in groups treated with dic complexes in comparable with dic treated group.

  5. Galaxy triplets in Sloan Digital Sky Survey Data Release 7 - III. Analysis of Configuration and Dynamics

    CERN Document Server

    Duplancic, Fernanda; Lambas, Diego García; O'Mill, Ana Laura


    We analyse the spatial configuration and the dynamical properties of a sample of 92 galaxy triplets obtained from the SDSS-DR7 (SDSS-triplets) restricted to have members with spectroscopic redshifts in the range $0.01\\le z \\le 0.14 $ and absolute r-band luminosities brighter than $M_r=-20.5$. The configuration analysis was performed through Agekyan & Anosova map (AA-map). We estimated dynamical parameters, namely the radius of the system, the velocity dispersion, a dimensionless crossing-time and the virial mass. We compared our results with those obtained for a sample of triplets from the catalogue "Isolated Triplets of Galaxies" (K-triplets) and a sample of Compact Groups. We have also studied a mock catalogue in order to compare real and projected configurations, and to estimate the three dimensional dynamical parameters of the triple systems. We found that the SDSS-triplets prefer alignment configurations while K-triplets present an uniform distribution in the AA-map. From the dynamical analysis we co...

  6. Orbifold Grand Unification: A Solution to the Doublet-Triplet Problem

    CERN Document Server

    Jia, Bei


    To solve the doublet-triplet splitting problem in SU(5) grand unified theories, we propose a four dimensional orbifold grand unified theory by acting Z2 on the SU(5) gauge group. Without an adjoint Higgs, the orbifold procedure breaks the SU(5) gauge symmetry down to the standard model gauge group, and removes the triplet component of the fundamental SU(5) Higgs. In the supersymmetric framework, we show that the orbifold procedure removes two triplet superfields of the Higgs multiplets and leaves us with the minimal supersymmetric standard model, which also solves the hierarchy problem and realizes gauge coupling unification. We also discuss possible UV completions of the orbifold theories.

  7. Influence of various functional groups on the relative stability of alkylperoxy triplet cations: A theoretical study (United States)

    Smith, Kenneth J.; Meloni, Giovanni


    CBS-QB3 energy calculations show that the formation of a stable triplet cation for alkylperoxy radicals is dependent on factors other than the stability of the daughter cations exclusively. We have found that in cases where the daughter ions are not capable of stabilizing the cation through hyperconjugation, it is possible for the triplet cation to be bound. In many circumstances, CBS-QB3 calculations have found bound triplet cation states with 'negative dissociation energies.' These results are attributed to the effects that electron donating/withdrawing substituents have on the spin and charge densities of the resulting cations.

  8. Molecular hosts for triplet emitters in organic light-emitting diodes and the corresponding working principle

    Institute of Scientific and Technical Information of China (English)


    This paper summarizes the mechanism and routes for excitation of triplet emitters in dopant emission based phosphorescent organic light-emitting diodes (PhOLEDs),providing a comprehensive overview of recent progress in molecular hosts for triplet emitters in PhOLEDs.Particularly,based on the nature of different hosts,e.g.,hole transporting,electron transporting or bipolar materials,in which the dopant emitters can be hosted to generate phosphorescence,the respective device performances are summarized and compared.Highlights are given to the relationships among the molecular structure,thermal stability,triplet energy,carrier mobility,molecular orbital energy level and their corresponding device performances.

  9. Triplet States of Thioflavin T in Fluorescent Molecular Rotor Model (United States)

    Kuz‧mitskii, V. A.; Stepuro, V. I.


    Quantum-chemical INDO/S calculations of Thiofl avin T have been carried out taking account of variation of the angle φ between the planes of the benzothiazole (BTZ) and dimethylaniline (DMA) rings. It was found that when the angle φ changes from 40° to 90° the energy of the triplet state increases by 4000 cm-1, whereas the energy of the singlet state S 1 decreases by 1900 cm-1 and reaches a minimum. The function {E}_{T_1}(φ) has a minimum at φ = 30°, which is 300 cm-1 less than at φ = 40°. The calculated T 1 S 0 interval at φ = 30-40° amounts to 15,600-16,000 cm-1, which agrees well with the phosphorescence data (17,100-17,400 cm-1). For φ = 80-90° the T 1, T 2 , and T 3 levels ( T 1 and T 2 are lower than S 1 ) are close to the S 1 level. The S 1 and T 3 levels intersect at φ 85°, and at φ = 90° the interval Δ {E}_{S_1{T}_3} amounts to only 100 cm-1 due to the small value of the exchange integral corresponding to electron transfer DMA → BTZ.

  10. Triplet superconductivity in oxide ferromagnetic interlayer of mesa-structure (United States)

    Ovsyannikov, G. A.; Y Constantinian, K.; Sheerman, A. E.; Shadrin, A. V.; Kislinski, Yu V.; Khaydukov, Yu N.; Mustafa, L.; Kalabukhov, A.; Winkler, D.


    We present experimental data on Nb-Au/La0.7Sr0.3MnO3/SrRuO3/YBa2Cu3O7-δ mesa- structure with in plane linear size 10÷50 μm. The mesa-structures were patterned from the epitaxial heterostructures fabricated by pulsed laser ablation and magnetron sputtering. Superconducting critical current was observed for mesa-structures with the interlayer thicknesses up to 50 nm. In the mesa-structures with just one, either La0.7Sr0.3MnO3 or SrRuO3 interlayer with a thickness larger than 10 nm no superconducting current was observed. The registered superconducting current for the mesa-structures with a thinner interlayer is attributed to pinholes. Obtained results are discussed in terms of superconducting long-range triplet generation at interfaces of superconductor and a composite ferromagnet consisting of ferromagnetic materials with non-collinear magnetization.

  11. An atlas of Calcium triplet spectra of active galaxies

    CERN Document Server

    Garcia-Rissmann, A; Asari, N V; Fernandes, R C; Schmitt, H; González-Delgado, R M; Storchi-Bergmann, T


    We present a spectroscopic atlas of active galactic nuclei covering the region around the 8498, 8542, 8662 Calcium triplet (CaT) lines. The sample comprises 78 objects, divided into 43 Seyfert 2s, 26 Seyfert 1s, 3 Starburst and 6 normal galaxies. The spectra pertain to the inner ~300 pc in radius, and thus sample the central kinematics and stellar populations of active galaxies. The data are used to measure stellar velocity dispersions (sigma_star) both with cross-correlation and direct fitting methods. These measurements are found to be in good agreement with each-other and with those in previous studies for objects in common. The CaT equivalent width is also measured. We find average values and sample dispersions of W_CaT of 4.6+/-2.0, 7.0 and 7.7+/-1.0 angstrons for Seyfert 1s, Seyfert 2s and normal galaxies, respectively. We further present an atlas of [SIII]\\lambda 9069 emission line profiles for a subset of 40 galaxies. These data are analyzed in a companion paper which addresses the connection between ...

  12. Radiative corrections to the Higgs couplings in the triplet model

    CERN Document Server

    Kikuchi, Mariko


    The feature of extended Higgs models can appear in the pattern of deviations from the Standard Model (SM) predictions in coupling constants of the SM-like Higgs boson ($h$). We can thus discriminate extended Higgs models by precisely measuring the pattern of deviations in the coupling constants of $h$, even when extra bosons are not found directly. In order to compare the theoretical predictions to the future precision data at the ILC, we must evaluate the theoretical predictions with radiative corrections in various extended Higgs models. In this talk, we give our comprehensive study for radiative corrections to various Higgs boson couplings of $h$ in the minimal Higgs triplet model (HTM). First, we define renormalization conditions in the model, and we calculate the Higgs coupling; $g\\gamma\\gamma, hWW, hZZ$ and $hhh$ at the one loop level. We then evaluate deviations in coupling constants of the SM-like Higgs boson from the predictions in the SM. We find that one-loop contributions to these couplings are su...

  13. Vortex lines in a ferromagnetic spin-triplet superconductor

    Institute of Scientific and Technical Information of China (English)

    Zhao Li; Yang Jie; Xie Qun-Ying; Tian Miao; Duan Yi-Shi


    Based on Duan's topological current theory,we show that in a ferromagnetic spin-triplet superconductor there is a topological defect of string structures which can be interpreted as vortex lines.Such defects are different from the Abrikosov vortices in one-component condensate systems.We investigate the inner topological structure of the vortex lines.The topological charge density,velocity,and topological current of the vortex lines can all be expressed in terms of δ function,which indicates that the vortices can only arise from the zero points of an order parameter field.The topological charges of vortex lines are quantized in terms of the Hopf indices and Brouwer degrees of φ-mapping.The divergence of the self-induced magnetic field can be rigorously determined by the corresponding order parameter fields and its expression also takes the form of a δ-like function.Finally,based on the implicit function theorem and the Taylor expansion,we conduct detailed studies on the bifurcation of vortex topological current and find different directions of the bifurcation.

  14. Noise filtering of composite pulses for singlet-triplet qubits (United States)

    Yang, Xu-Chen; Wang, Xin


    Semiconductor quantum dot spin qubits are promising candidates for quantum computing. In these systems, the dynamically corrected gates offer considerable reduction of gate errors and are therefore of great interest both theoretically and experimentally. They are, however, designed under the static-noise model and may be considered as low-frequency filters. In this work, we perform a comprehensive theoretical study of the response of a type of dynamically corrected gates, namely the supcode for singlet-triplet qubits, to realistic 1/f noises with frequency spectra 1/ωα. Through randomized benchmarking, we have found that supcode offers improvement of the gate fidelity for α  1 and the improvement becomes exponentially more pronounced with the increase of the noise exponent in the range 1  α ≤ 3 studied. On the other hand, for small α, supcode will not offer any improvement. The δJ-supcode, specifically designed for systems where the nuclear noise is absent, is found to offer additional error reduction than the full supcode for charge noises. The computed filter transfer functions of the supcode gates are also presented. PMID:27383129

  15. Noise filtering of composite pulses for singlet-triplet qubits (United States)

    Yang, Xu-Chen; Wang, Xin


    Semiconductor quantum dot spin qubits are promising candidates for quantum computing. In these systems, the dynamically corrected gates offer considerable reduction of gate errors and are therefore of great interest both theoretically and experimentally. They are, however, designed under the static-noise model and may be considered as low-frequency filters. In this work, we perform a comprehensive theoretical study of the response of a type of dynamically corrected gates, namely the SUPCODE for singlet-triplet qubits, to realistic 1/f noises with frequency spectra 1/ωα. Through randomized benchmarking, we have found that SUPCODE offers improvement of the gate fidelity for α  1 and the improvement becomes exponentially more pronounced with the increase of the noise exponent in the range 1  α ≤ 3 studied. On the other hand, for small α, SUPCODE will not offer any improvement. The δJ-SUPCODE, specifically designed for systems where the nuclear noise is absent, is found to offer additional error reduction than the full SUPCODE for charge noises. The computed filter transfer functions of the supcode gates are also presented.

  16. Singlet and triplet excited state properties of natural chlorophylls and bacteriochlorophylls

    Energy Technology Data Exchange (ETDEWEB)

    Niedzwiedzki, Dariusz; Blankenship, R. E.


    Ten naturally occurring chlorophylls (a, b, c{sub 2}, d) and bacteriochlorophylls (a, b, c, d, e, g) were purified and studied using the optical spectroscopic techniques of both steady state and time-resolved absorption and fluorescence. The studies were carried out at room temperature in nucleophilic solvents in which the central Mg is hexacoordinated. The comprehensive studies of singlet excited state lifetimes show a clear dependency on the structural features of the macrocycle and terminal substituents. The wide-ranging studies of triplet state lifetime demonstrate the existence of an energy gap law for these molecules. The knowledge of the dynamics and the energies of the triplet state that were obtained in other studies allowed us to construct an energy gap law expression that can be used to estimate the triplet state energies of any (B)chlorophyll molecule from its triplet lifetime obtained in a liquid environment.

  17. The origin of efficient triplet state population in sulfur-substituted nucleobases (United States)

    Mai, Sebastian; Pollum, Marvin; Martínez-Fernández, Lara; Dunn, Nicholas; Marquetand, Philipp; Corral, Inés; Crespo-Hernández, Carlos E.; González, Leticia


    Elucidating the photophysical mechanisms in sulfur-substituted nucleobases (thiobases) is essential for designing prospective drugs for photo- and chemotherapeutic applications. Although it has long been established that the phototherapeutic activity of thiobases is intimately linked to efficient intersystem crossing into reactive triplet states, the molecular factors underlying this efficiency are poorly understood. Herein we combine femtosecond transient absorption experiments with quantum chemistry and nonadiabatic dynamics simulations to investigate 2-thiocytosine as a necessary step to unravel the electronic and structural elements that lead to ultrafast and near-unity triplet-state population in thiobases in general. We show that different parts of the potential energy surfaces are stabilized to different extents via thionation, quenching the intrinsic photostability of canonical DNA and RNA nucleobases. These findings satisfactorily explain why thiobases exhibit the fastest intersystem crossing lifetimes measured to date among bio-organic molecules and have near-unity triplet yields, whereas the triplet yields of canonical nucleobases are nearly zero.

  18. The photochemistry of lipoic acid: photoionization and observation of a triplet excited state of a disulfide. (United States)

    Bucher, Götz; Lu, Changyuan; Sander, Wolfram


    Under short-wavelength UV irradiation, lipoic acid (LipSS) and its reduced form, dihydrolipoic acid (DHLA), undergo photoionization processes through a bi- or monophotonic pathway. After ionization, the LipSS radical cation (LipSS*+) and radical anion (LipSS*-) are generated. LipSS*- can be converted to equimolar amounts of LipSS and DHLA through second-order decay. Triplet acetone can be quenched by LipSS and DHLA with a rate close to the diffusion-controlled limit. The mechanism was further confirmed by continuous irradiation experiments. When LipSS is directly irradiated with UVA light, the first excited triplet state of LipSS is observed, with a lifetime tau=75 ns. Characteristic reactions include triplet energy transfer to oxygen and beta-carotene and addition to isoprene. The lifetime of triplet LipSS is also shortened by addition of water and methanol.

  19. Sensitized Triplet Formation of Chlorophyll-A and beta-Carotene

    DEFF Research Database (Denmark)

    Jensen, Nina Mejlhede; Wilbrandt, Robert Walter; Pagsberg, Palle Bjørn


    The naphthalene-sensitized formation of triplet excited chlorophyll-a (Chl-a) and all-transß-carotene has been studied by pulse radiolysis. The rate constants for transfer of triplet energy from naphthalene to Chl-a and all-transß-carotene in benzene at 25°C are (3.6 ± 0.6)·109M-1 s-1 and (10.7 ± 1...

  20. Spiro-linked hyperbranched architecture in electrophosphorescent conjugated polymers for tailoring triplet energy back transfer. (United States)

    Shao, Shiyang; Ma, Zhihua; Ding, Junqiao; Wang, Lixiang; Jing, Xiabin; Wang, Fosong


    A spiro-linked hyperbranched architecture has been incorporated into electrophosphorescent conjugated polymers for the first time, aiming at simultaneously tailoring the intra- and intermolecular triplet energy back transfer from the phosphorescent guest to the conjugated polymer host. Based on a prototype with this unique structure, slower decay of triplet excitons, and 5-8 fold enhancement of device efficiencies are obtained compared with the conventional blending counterpart.

  1. The models of proton assisted and the unassisted formation of CGC base triplets. (United States)

    Medhi, Chitrani


    The triple helix is formed by combining a double and a single strand DNAs in low pH and dissociates in high pH. Under such conditions, protonation of cytosine in the single strand is necessary for triplex formation where cytosine-guanine-cytosine (CGC+) base triplet stabilizes the triple helix. The mechanism of CGC+ triplet formation from guanine-cytosine (GC) and a protonated cytosine (C+) shows the importance of N3 proton. Similarly in the case of CGC (unprotonated) triplet, the donor acceptor H-bond at N3 hydrogen of the cytosine analog (C) initiates the interaction with GC. The correspondence between the two models of triplets, CGC+ and CGC, unambiguously assigned that protonation at N3 cytosine in low pH to be the first step in triplet formation, but a donor acceptor triplet (CGC) can be designed without involving a proton in the Hoogsteen H-bond. Further, the bases of cytosine analogue also show the capability of forming Watson Crick (WC) H-bonds with guanine.

  2. Triplet state in photosystem II reaction centers as studied by 130 GHz EPR

    Energy Technology Data Exchange (ETDEWEB)

    Pashenko, S.V.; Proskuryakov, I.I.; Germano, M.; Gorkom, H.J. van; Gast, P


    The triplet state in the reaction centers of photosystem II was studied by high-field/high-frequency (130 GHz) EPR in the temperature range 50-90 K. At 50 K, the zero-field splitting parameters of the EPR spectrum correspond well to those of a chlorophyll monomer, in agreement with earlier studies. In the high magnetic field of 4.6 T employed in this study, the g-anisotropy of the triplet state becomes apparent and leads to a shift of the canonical positions of the triplet EPR spectrum. Assuming that triplet g- and zero-field tensors are coaxial, the principal values of the triplet g-tensor are determined to be 2.00324, 2.00306 and 2.00231 with an error of {+-}0.00004. Lifting this assumption results in higher g-anisotropy. At higher temperatures, the shape of the spectra changes significantly. Triplet excitation hopping involving the accessory chlorophyll B{sub A} and P{sub A} or P{sub B} (equivalents of the special pair bacteriochlorophylls of the bacterial reaction centers) can partially explain those changes, but the most prominent features indicate that also the electron acceptor I{sub A} (a pheophytin molecule) must be involved.

  3. Ab inito study on triplet excitation energy transfer in photosynthetic light-harvesting complexes. (United States)

    You, Zhi-Qiang; Hsu, Chao-Ping


    We have studied the triplet energy transfer (TET) for photosynthetic light-harvesting complexes, the bacterial light-harvesting complex II (LH2) of Rhodospirillum molischianum and Rhodopseudomonas acidophila, and the peridinin-chlorophyll a protein (PCP) from Amphidinium carterae. The electronic coupling factor was calculated with the recently developed fragment spin difference scheme (You and Hsu, J. Chem. Phys. 2010, 133, 074105), which is a general computational scheme that yields the overall coupling under the Hamiltonian employed. The TET rates were estimated based on the couplings obtained. For all light-harvesting complexes studied, there exist nanosecond triplet energy transfer from the chlorophylls to the carotenoids. This result supports a direct triplet quenching mechanism for the photoprotection function of carotenoids. The TET rates are similar for a broad range of carotenoid triplet state energy, which implies a general and robust TET quenching role for carotenoids in photosynthesis. This result is also consistent with the weak dependence of TET kinetics on the type or the number of π conjugation lengths in the carotenoids and their analogues reported in the literature. We have also explored the possibility of forming triplet excitons in these complexes. In B850 of LH2 or the peridinin cluster in PCP, it is unlikely to have triplet exciton since the energy differences of any two neighboring molecules are likely to be much larger than their TET couplings. Our results provide theoretical limits to the possible photophysics in the light-harvesting complexes.

  4. Exploring Higgs Triplet Models via Vector Boson Scattering at the LHC

    CERN Document Server

    Godfrey, Stephen


    We present the results of a study of Higgs triplet boson production arising in the Littlest Higgs, Left-Right Symmetric, and Georgi-Machacek models in the W^\\pm W^\\pm, W^\\pm Z, W^+ W^-, and Z Z channels at the LHC. We focus on the "gold-plated" purely leptonic decay modes and consider the irreducible electroweak, QCD, and t-quark backgrounds, applying a combination of forward-jet-tagging, central-jet-vetoing, and stringent leptonic cuts to suppress the backgrounds. We find that, given the constraints on the triplet vacuum expectation value (vev), considerable luminosity is required to observe Higgs triplet bosons in vector boson scattering. Observing a Higgs triplet at the LHC is most promising in the Georgi-Machacek model due to a weaker constraint on the triplet vev. In this model, we find that a Higgs triplet boson with a mass of 1.0 (1.5) TeV can be observed at the LHC with an integrated luminosity as low as 41 (119) fb^{-1} in the W^\\pm W^\\pm channel and as low as 171 (474) fb^{-1} in the W^\\pm Z channel...

  5. Weight growth of triplet infants from birth to twelve years of age. (United States)

    Yokoyama, Yoshie; Pitkäniemi, Janne; Kaprio, Jaakko; Silventoinen, Karri


    We analyzed the characteristics associated with the growth in weight of Japanese triplets from birth to 12 years of age. The study included 376 mothers and their 1,128 triplet children, who were born between 1978 and 2006. Data were collected through a mailed questionnaire sent to the mothers asking for information recorded in medical records. For these births, data on triplets' weight growth, gestational age, sex, parity, maternal age at delivery, maternal height, and maternal body mass index were obtained from records in the Maternal and Child Health Handbooks and records in the school where children receive health check-ups. The weight deficit of the triplets compared to the general population of Japan remained between 10% and 17% until 12 years of age. Moreover, at 12 years of age, the differences of weight between the general population and triplets were approximately -4.75 kg for boys and -6.00 kg for girls. Very low birth weight had the strongest contribution to body weight until 8 years of age. After 8 years of age, maternal body mass index was a significant factor affecting the weight of triplets until 12 years of age.

  6. π-Conjugated Organometallic Isoindigo Oligomer and Polymer Chromophores: Singlet and Triplet Excited State Dynamics and Application in Polymer Solar Cells. (United States)

    Goswami, Subhadip; Gish, Melissa K; Wang, Jiliang; Winkel, Russell W; Papanikolas, John M; Schanze, Kirk S


    An isoindigo based π-conjugated oligomer and polymer that contain cyclometalated platinum(II) "auxochrome" units were subjected to photophysical characterization, and application of the polymer in bulk heterojunction polymer solar cells with PCBM acceptor was examined. The objective of the study was to explore the effect of the heavy metal centers on the excited state properties, in particular, intersystem crossing to a triplet (exciton) state, and further how this would influence the performance of the organometallic polymer in solar cells. The materials were characterized by electrochemistry, ground state absorption, emission, and picosecond-nanosecond transient absorption spectroscopy. Electrochemical measurements indicate that the cyclometalated units have a significant impact on the HOMO energy level of the chromophores, but little effect on the LUMO, which is consistent with localization of the LUMO on the isoindigo acceptor unit. Picosecond-nanosecond transient absorption spectroscopy reveals a transient with ∼100 ns lifetime that is assigned to a triplet excited state that is produced by intersystem crossing from a singlet state on a time scale of ∼130 ps. This is the first time that a triplet state has been observed for isoindigo π-conjugated chromophores. The performance of the polymer in bulk heterojunction solar cells was explored with PC61BM as an acceptor. The performance of the cells was optimum at a relatively high PCBM loading (1:6, polymer:PCBM), but the overall efficiency was relatively low with power conversion efficiency (PCE) of 0.22%. Atomic force microscopy of blend films reveals that the length scale of the phase separation decreases with increasing PCBM content, suggesting a reason for the increase in PCE with acceptor loading. Energetic considerations show that the triplet state in the polymer is too low in energy to undergo charge separation with PCBM. Further, due to the relatively low LUMO energy of the polymer, charge transfer

  7. Accessing the Long-Lived Triplet Excited States in Transition-Metal Complexes: Molecular Design Rationales and Applications. (United States)

    Cui, Xiaoneng; Zhao, Jianzhang; Mohmood, Zafar; Zhang, Caishun


    Transition-metal complex triplet photosensitizers are versatile compounds that have been widely used in photocatalysis, photovoltaics, photodynamic therapy (PDT) and triplet-triplet annihilation (TTA) upconversion. The principal photophysical processes in these applications are the intermolecular energy transfer or electron transfer. One of the major challenges facing these triplet photosensitizers is the short triplet-state lifetime, which is detrimental to the above-mentioned photophysical processes. In order to address this challenge, transition-metal complexes showing long-lived triplet excited states are highly desired. This review article summarizes the development of this fascinating area, including the molecular design rationales, the principal photophysical properties, and the applications of these complexes in PDT and TTA upconversion.

  8. Laser flash photolysis study on 9-phenylxanthenium tetrafluoroborate: Identification of new features due to the triplet state

    Indian Academy of Sciences (India)

    Sanghamitra Banerjee; Anunay Samanta


    Laser flash photolysis study on highly fluorescent and stable salt of 9-phenylxanthenium cation in neutral condition has been carried out for the first time. A new transient absorption band of this extensively studied system that perhaps remained buried under the fluorescence envelope and hitherto undetected has been identified and attributed to the triplet state of the system. This oxygen-insensitive triplet-triplet absorption band in the 480-600 nm range is expected to trigger new studies exploring the reactivity of the triplet state of this system, which has so far received very little attention.

  9. Preorganized Chromophores Facilitate Triplet Energy Migration, Annihilation and Upconverted Singlet Energy Collection. (United States)

    Mahato, Prasenjit; Yanai, Nobuhiro; Sindoro, Melinda; Granick, Steve; Kimizuka, Nobuo


    Photon upconversion (UC) based on triplet-triplet annihilation (TTA) has the potential to enhance significantly photovoltaic and photocatalytic efficiencies by harnessing sub-bandgap photons, but the progress of this field is held back by the chemistry problem of how to preorganize multiple chromophores for efficient UC under weak solar irradiance. Recently, the first maximization of UC quantum yield at solar irradiance was achieved using fast triplet energy migration (TEM) in metal-organic frameworks (MOFs) with ordered acceptor arrays, but at the same time, a trade-off between fast TEM and high fluorescence efficiency was also found. Here, we provide a solution for this trade-off issue by developing a new strategy, triplet energy migration, annihilation and upconverted singlet energy collection (TEM-UPCON). The porous structure of acceptor-based MOF crystals allows triplet donor molecules to be accommodated without aggregation. The surface of donor-doped MOF nanocrystals is modified with highly fluorescent energy collectors through coordination bond formation. Thanks to the higher fluorescence quantum yield of surface-bound collectors than parent MOFs, the implementation of the energy collector greatly improves the total UC quantum yield. The UC quantum yield maximization behavior at ultralow excitation intensity was retained because the TTA events take place only in the MOF acceptors. The TEM-UPCON concept may be generalized to collectors with various functions and would lead to quantitative harvesting of upconverted energy, which is difficult to achieve in common molecular diffusion-based systems.

  10. Long-lived two-dimensional triplet magnetoexcitons in a Hall insulator (United States)

    Kulik, L. V.; Gorbunov, A. V.; Zhuravlev, A. S.; Timofeev, V. B.; Kukushkin, I. V.


    An experimental technique is developed to perform photoexcitation of an ensemble of translationinvariant triplet excitons, to manipulate this ensemble, and to detect the properties of its components. In particular, the influence of temperature on the radiationless decay during the relaxation of an exciton spin into the ground state of a Hall insulator at a filling factor ν = 2 is studied. The generation of photoexcited electrons and holes is controlled using photoinduced resonance reflection spectra, which makes it possible to estimate the density of light-generated electron-hole pairs and to independently control the self-consistent generation of electrons at the first Landau level and holes (vacancies) at the ground (zero) cyclotron electronic level. The existence of triplet excitons is established from inelastic light scattering spectra, which are used to determine the singlet-triplet exciton splitting. The lifetimes of triplet excitons, which are closely related to the relaxation time of an electron spin, are extremely long: they reach 100 μs in perfect GaAs/AlGaAs heterostructures with a high mobility of two-dimensional electrons at low temperatures. These long spin relaxation times are qualitatively explained, and the expected collective behavior of high-density triplet magnetoexcitons at sufficiently low temperatures, which is related to their Bose nature, is discussed.

  11. Triplet State Formation in Photovoltaic Blends of DPP-Type Copolymers and PC71BM

    KAUST Repository

    Ochsmann, Julian R.


    The exciton dynamics in pristine films of two structurally related low-bandgap diketopyrrolopyrrole (DPP)-based donor–acceptor copolymers and the photophysical processes in bulk heterojunction solar cells using DPP copolymer:PC71BM blends are investigated by broadband transient absorption (TA) pump-probe experiments covering the vis–near-infrared spectral and fs–μs dynamic range. The experiments reveal surprisingly short exciton lifetimes in the pristine poly­mer films in conjunction with fast triplet state formation. An in-depth analysis of the TA data by multivariate curve resolution analysis shows that in blends with fullerene as acceptor ultrafast exciton dissociation creates charge carriers, which then rapidly recombine on the sub-ns timescale. Furthermore, at the carrier densities created by pulsed laser excitation the charge carrier recombination leads to a substantial population of the polymer triplet state. In fact, virtually quantitative formation of triplet states is observed on the sub-ns timescale. However, the quantitative triplet formation on the sub-ns timescale is not in line with the power conversion efficiencies of devices indicating that triplet state formation is an intensity-dependent process in these blends and is reduced under solar illumination conditions, as free charge carriers can be extracted from the photoactive layer in devices.

  12. Matrix genetics, part 1: permutations of positions in triplets and symmetries of genetic matrices

    CERN Document Server

    Petoukhov, Sergey V


    The hidden connection between the degeneracy of the vertebrate mitochondria genetic code and the positional permutations inside genetic triplets is described. The Kronecker family of the genetic matrices is investigated, which is based on the genetic matrix [C A; U G], where C, A, U, G are the letters of the genetic alphabet. The natural system of binary numeration of genetic multiplets in the genetic matrices is proposed. The matrix [C A; U G] in the third Kronecker power is the (8*8)-matrix, which contains 64 triplets. When 64 triplets in this matrix are numbered in accordance with the natural system, the coincidence with the famous table of 64 hexagrams of the ancient Chinese book "I Ching" arises. It is significant that peculiarities of the degeneracy of the vertebrate mitochondria genetic code are reflected in the symmetrical black-and-white mosaic of this genetic (8*8)-matrix of 64 triplets. This matrix is reformed into a new mosaic matrix when internal positions in all triplets are permuted simultaneou...

  13. Energy harvesting of non-emissive triplet excitons in tetracene by emissive PbS nanocrystals (United States)

    Thompson, Nicholas J.; Wilson, Mark W. B.; Congreve, Daniel N.; Brown, Patrick R.; Scherer, Jennifer M.; Bischof, Thomas S.; Wu, Mengfei; Geva, Nadav; Welborn, Matthew; Voorhis, Troy Van; Bulović, Vladimir; Bawendi, Moungi G.; Baldo, Marc A.


    Triplet excitons are ubiquitous in organic optoelectronics, but they are often an undesirable energy sink because they are spin-forbidden from emitting light and their high binding energy hinders the generation of free electron-hole pairs. Harvesting their energy is consequently an important technological challenge. Here, we demonstrate direct excitonic energy transfer from ‘dark’ triplets in the organic semiconductor tetracene to colloidal PbS nanocrystals, thereby successfully harnessing molecular triplet excitons in the near infrared. Steady-state excitation spectra, supported by transient photoluminescence studies, demonstrate that the transfer efficiency is at least (90 ± 13)%. The mechanism is a Dexter hopping process consisting of the simultaneous exchange of two electrons. Triplet exciton transfer to nanocrystals is expected to be broadly applicable in solar and near-infrared light-emitting applications, where effective molecular phosphors are lacking at present. In particular, this route to ‘brighten’ low-energy molecular triplet excitons may permit singlet exciton fission sensitization of conventional silicon solar cells.

  14. Investigation of the role of triplet states in the Wulf bands of ozone (United States)

    Braunstein, M.; Martin, R. L.; Hay, P. J.


    Results of spin-orbit interaction calculations on the three lowest triplet states of ozone, 3B2, 3A2, and 3B1, are presented. These calculations use a one-electron, one-center approximation of the spin-orbit operator and a modest number of configurations within a 3s2p1d basis to estimate the amount of singlet character in these predominantly triplet states and triplet character in the predominantly singlet ground state. The results are given in the context of recent studies which predict that one of these triplet states gives rise to the Wulf optical absorption bands of ozone, a series of weak diffuse peaks in the near infrared, just above the O2+O dissociation threshold. Without spin-orbit coupling, these triplet states are spin forbidden from the singlet ozone ground state, 1A1. The present results point to the 3A2 and 3B1 states as playing a possible role in the Wulf bands, but more complete calculations will be needed to confirm this.

  15. Energy-donor phosphorescence quenching study of triplet–triplet energy transfer between UV absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Azusa; Nakabai, Yuya [Department of Chemistry, Graduate School of Engineering, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan); Oguchi-Fujiyama, Nozomi; Miyazawa, Kazuyuki [Shiseido Research Center, Hayabuchi, Tsuzuki-ku, Yokohama 224-8558 (Japan); Yagi, Mikio, E-mail: [Department of Chemistry, Graduate School of Engineering, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)


    The intermolecular triplet–triplet energy transfer from a photounstable UV-A absorber, 4-tert-butyl-4′-methoxydibenzoylmethane (BMDBM), to UV-B absorbers, 2-ethylhexyl 4-methoxycinnamate (octyl methoxycinnamate, OMC), octocrylene (OCR) and dioctyl 4-methoxybenzylidenemalonate (DOMBM) has been observed using a 355 nm laser excitation in rigid solutions at 77 K. The decay curves of the energy-donor phosphorescence in the presence of the UV-B absorbers deviate from the exponential decay at the initial stage of the decay. The Stern–Volmer formulation is not valid in rigid solutions because molecular diffusion is impossible. The experimental results indicate that the rate constant of triplet–triplet energy transfer from BMDBM to the UV-B absorbers, k{sub T–T}, decreases in the following order: k{sub T–T} (BMDBM–DOMBM)>k{sub T–T} (BMDBM–OMC)≥k{sub T–T} (BMDBM–OCR). The presence of DOMBM enhances the photostability of the widely used combination of UV-A and UV-B absorbers, BMDBM and OCR. The effects of the triplet–triplet energy transfer on the photostability of BMDBM are discussed. - Highlights: • The intermolecular triplet–triplet energy transfer between UV absorbers was observed. • The phosphorescence decay deviates from exponential at the initial stage of decay. • The effects of triplet–triplet energy transfer on the photostability are discussed.

  16. Physicochemical impact studies of gamma rays on "aspirin" analgesics drug and its metal complexes in solid form: Synthesis, spectroscopic and biological assessment of Ca(II), Mg(II), Sr(II) and Ba(II) aspirinate complexes (United States)

    Refat, Moamen S.; Sharshar, T.; Elsabawy, Khaled M.; Heiba, Zein K.


    Metal aspirinate complexes, M2(Asp)4, where M is Mg(II), Ca(II), Sr(II) or Ba(II) are formed by refluxed of aspirin (Asp) with divalent non-transition metal ions of group (II) and characterized by elemental analysis and spectroscopic measurements (infrared, electronic, 1H NMR, Raman, X-ray powder diffraction and scanning electron microscopy). Elemental analysis of the chelates suggests the stoichiometry is 1:2 (metal:ligand). Infrared spectra of the complexes agree with the coordination to the central metal atom through three donation sites of two oxygen atoms of bridge bidentate carboxylate group and oxygen atom of sbnd Cdbnd O of acetyl group. Infrared spectra coupled with the results of elemental analyzes suggested a distorted octahedral structure for the M(II) aspirinate complexes. Gamma irradiation was tested as a method for stabilization of aspirin as well as their complexes. The effect of gamma irradiation, with dose of 80 Gy, on the properties of aspirinate complexes was studied. The aspirinate chelates have been screened for their in vitro antibacterial activity against four bacteria, gram-positive (Bacillus subtilis and Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) and two strains of fungus (Aspergillus flavus and Candida albicans). The metal chelates were shown to possess more antibacterial activity than the free aspirin chelate.

  17. Sub-ns triplet state formation by non-geminate recombination in PSBTBT:PC 70 BM and PCPDTBT:PC 60 BM organic solar cells

    KAUST Repository

    Etzold, Fabian


    The solid-state morphology and photo-generated charge carrier dynamics in low-bandgap polymer:fullerene bulk heterojunction photovoltaic blends using the donor–acceptor type copolymers PCPDTBT or its silicon-substituted analogue PSBTBT as donors are compared by two-dimensional (2D) solid-state nuclear magnetic resonance (NMR) and femto-to microsecond broadband Vis-NIR transient absorption (TA) pump–probe spectroscopy. The 2D solid-state NMR experiments demonstrate that the film morphology of PCPDTBT:PC60BM blends processed with additives such as octanedithiol (ODT) are similar to those of PSBTBT:PC60BM blends in terms of crystallinity, phase segregation, and interfacial contacts. The TA experiments and analysis of the TA data by multivariate curve resolution (MCR) reveal that after exciton dissociation and free charge formation, fast sub-nanosecond non-geminate recombination occurs which leads to a substantial population of the polymer\\'s triplet state. The extent to which triplet states are formed depends on the initial concentration of free charges, which itself is controlled by the microstructure of the blend, especially in case of PCPDTBT:PC60BM. Interestingly, PSBTBT:PC70BM blends show a higher charge generation efficiency, but less triplet state formation at similar free charge carrier concentrations. This indicates that the solid-state morphology and interfacial structures of PSBTBT:PC70BM blends reduces non-geminate recombination, leading to superior device performance compared to optimized PCPDTBT:PC60BM blends.

  18. A New Track Reconstruction Algorithm suitable for Parallel Processing based on Hit Triplets and Broken Lines (United States)

    Schöning, André


    Track reconstruction in high track multiplicity environments at current and future high rate particle physics experiments is a big challenge and very time consuming. The search for track seeds and the fitting of track candidates are usually the most time consuming steps in the track reconstruction. Here, a new and fast track reconstruction method based on hit triplets is proposed which exploits a three-dimensional fit model including multiple scattering and hit uncertainties from the very start, including the search for track seeds. The hit triplet based reconstruction method assumes a homogeneous magnetic field which allows to give an analytical solutions for the triplet fit result. This method is highly parallelizable, needs fewer operations than other standard track reconstruction methods and is therefore ideal for the implementation on parallel computing architectures. The proposed track reconstruction algorithm has been studied in the context of the Mu3e-experiment and a typical LHC experiment.

  19. A New Track Reconstruction Algorithm suitable for Parallel Processing based on Hit Triplets and Broken Lines

    CERN Document Server

    Schöning, Andre


    Track reconstruction in high track multiplicity environments at current and future high rate particle physics experiments is a big challenge and very time consuming. The search for track seeds and the fitting of track candidates are usually the most time consuming steps in the track reconstruction. Here, a new and fast track reconstruction method based on hit triplets is proposed which exploits a three-dimensional fit model including multiple scattering and hit uncertainties from the very start, including the search for track seeds. The hit triplet based reconstruction method assumes a homogeneous magnetic field which allows to give an analytical solutions for the triplet fit result. This method is highly parallelizable, needs fewer operations than other standard track reconstruction methods and is therefore ideal for the implementation on parallel computing architectures. The proposed track reconstruction algorithm has been studied in the context of the Mu3e-experiment and a typical LHC experiment.

  20. Inelastic collisions of ultracold triplet Rb$_\\textbf{2}$ molecules in the rovibrational ground state

    CERN Document Server

    Drews, Björn; Jachymski, Krzysztof; Idziaszek, Zbigniew; Denschlag, Johannes Hecker


    Exploring inelastic and reactive collisions on the quantum level is a main goal of the developing field of ultracold chemistry. We present first experimental studies of inelastic collisions of metastable ultracold triplet molecules in the vibrational ground state. The measurements are performed with nonpolar Rb$_2$ dimers which are prepared in precisely-defined quantum states and trapped in an array of quasi-1D potential tubes. We investigate collisions of molecules in the lowest triplet energy level where any inelastic process requires a relaxation to the singlet state. These are compared to two sets of collision experiments, carried out either with triplet molecules that have two quanta of rotational angular momentum or with vibrationally highly excited Feshbach molecules. We find no evidence for suppression of the inelastic collisions due to the necessary spin-flip, shedding light on this so far unsettled issue. For each of the molecular states studied here, we extract the decay rate constant and compare t...

  1. Theoretical study of the intensity of chemically induce dynamic electron polarization of radical-triplet pairs

    Institute of Scientific and Technical Information of China (English)

    XU Xin-sheng; ZHANG Xian-yi; ZHANG Wei-jun; CUI Zhi-feng; LU Tong-xing


    Considering the interaction between excited triplet molecule and doublet radical, based on the second-order perturbation theory and the motion equation of density matrix, the polarization intensity of RTPM were theoretically calculated with the overpopulated doublet spin states and quartet spin states of radical-triplet pairs as initial conditions respectively. The results of calculation indicate that the net emissive polarization and the net absorptive polarization on the radical result from the zero-field-splitting (zfs) and the multiplet A/E and E/A polarization result from hyperfine (hf) interactions of the triplet molecule. The hyperfine related A+A/E or E+E/A CIDEP on the radical were the overpopulation of the net absorptive or emissive polarization and multiplet A/E or E/A polarization..

  2. Conditions for describing triplet states in reduced density matrix functional theory

    CERN Document Server

    Theophilou, Iris; Helbig, Nicole


    We consider necessary conditions for the one body-reduced density matrix (1RDM) to correspond to a triplet wave-function of a two electron system. The conditions concern the occupation numbers and are different for the high spin projections, $S_z=\\pm 1$, and the $S_z=0$ projection. We employ these conditions in reduced density matrix functional theory calculations for the triplet excitations of two electron systems. In addition, we propose that these conditions can be used in the calculation of triplet states of systems with more than two electrons by restricting the active space and assess this procedure in calculations for a few atomic and molecular systems. We show that the quality of the optimal 1RDMs improves by applying the conditions in all the cases we studied.

  3. Triplet excited state properties in variable gap π-conjugated donor–acceptor–donor chromophores

    KAUST Repository

    Cekli, Seda


    A series of variable band-gap donor–acceptor–donor (DAD) chromophores capped with platinum(II) acetylide units has been synthesized and fully characterized by electrochemical and photophysical methods, with particular emphasis placed on probing triplet excited state properties. A counter-intuitive trend of increasing fluorescence quantum efficiency and lifetime with decreasing excited state energy (optical gap) is observed across the series of DAD chromophores. Careful study of the excited state dynamics, including triplet yields (as inferred from singlet oxygen sensitization), reveals that the underlying origin of the unusual trend in the fluorescence parameters is that the singlet–triplet intersystem crossing rate and yield decrease with decreasing optical gap. It is concluded that the rate of intersystem crossing decreases as the LUMO is increasingly localized on the acceptor unit in the DAD chromophore, and this result is interpreted as arising because the extent of spin–orbit coupling induced by the platinum heavy metal centers decreases as the LUMO is more localized on the acceptor. In addition to the trend in intersystem crossing, the results show that the triplet decay rates follow the Energy Gap Law correlation over a 1.8 eV range of triplet energy and 1000-fold range of triplet decay rates. Finally, femtosecond transient absorption studies for the DAD chromophores reveals a strong absorption in the near-infrared region which is attributed to the singlet excited state. This spectral band appears to be general for DAD chromophores, and may be a signature of the charge transfer (CT) singlet excited state.

  4. Codon size reduction as the origin of the triplet genetic code.

    Directory of Open Access Journals (Sweden)

    Pavel V Baranov

    Full Text Available The genetic code appears to be optimized in its robustness to missense errors and frameshift errors. In addition, the genetic code is near-optimal in terms of its ability to carry information in addition to the sequences of encoded proteins. As evolution has no foresight, optimality of the modern genetic code suggests that it evolved from less optimal code variants. The length of codons in the genetic code is also optimal, as three is the minimal nucleotide combination that can encode the twenty standard amino acids. The apparent impossibility of transitions between codon sizes in a discontinuous manner during evolution has resulted in an unbending view that the genetic code was always triplet. Yet, recent experimental evidence on quadruplet decoding, as well as the discovery of organisms with ambiguous and dual decoding, suggest that the possibility of the evolution of triplet decoding from living systems with non-triplet decoding merits reconsideration and further exploration. To explore this possibility we designed a mathematical model of the evolution of primitive digital coding systems which can decode nucleotide sequences into protein sequences. These coding systems can evolve their nucleotide sequences via genetic events of Darwinian evolution, such as point-mutations. The replication rates of such coding systems depend on the accuracy of the generated protein sequences. Computer simulations based on our model show that decoding systems with codons of length greater than three spontaneously evolve into predominantly triplet decoding systems. Our findings suggest a plausible scenario for the evolution of the triplet genetic code in a continuous manner. This scenario suggests an explanation of how protein synthesis could be accomplished by means of long RNA-RNA interactions prior to the emergence of the complex decoding machinery, such as the ribosome, that is required for stabilization and discrimination of otherwise weak triplet codon

  5. iTriplet, a rule-based nucleic acid sequence motif finder

    Directory of Open Access Journals (Sweden)

    Gunderson Samuel I


    Full Text Available Abstract Background With the advent of high throughput sequencing techniques, large amounts of sequencing data are readily available for analysis. Natural biological signals are intrinsically highly variable making their complete identification a computationally challenging problem. Many attempts in using statistical or combinatorial approaches have been made with great success in the past. However, identifying highly degenerate and long (>20 nucleotides motifs still remains an unmet challenge as high degeneracy will diminish statistical significance of biological signals and increasing motif size will cause combinatorial explosion. In this report, we present a novel rule-based method that is focused on finding degenerate and long motifs. Our proposed method, named iTriplet, avoids costly enumeration present in existing combinatorial methods and is amenable to parallel processing. Results We have conducted a comprehensive assessment on the performance and sensitivity-specificity of iTriplet in analyzing artificial and real biological sequences in various genomic regions. The results show that iTriplet is able to solve challenging cases. Furthermore we have confirmed the utility of iTriplet by showing it accurately predicts polyA-site-related motifs using a dual Luciferase reporter assay. Conclusion iTriplet is a novel rule-based combinatorial or enumerative motif finding method that is able to process highly degenerate and long motifs that have resisted analysis by other methods. In addition, iTriplet is distinguished from other methods of the same family by its parallelizability, which allows it to leverage the power of today's readily available high-performance computing systems.

  6. Transient absorption probe of intermolecular triplet excimer of naphthalene in fluid solutions: Identification of the species based on comparison to the intramolecular triplet excimers of covalently-linked dimers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Kofron, W.G.; Kong, S.; Rajesh, C.S.; Modarelli, D.A.; Lim, E.C.


    The authors report here the observation of the laser-induced transient absorption spectrum of intermolecular triplet excimers of naphthalene in fluid solution. This assignment is confirmed by comparison to the transient absorption spectra of the intramolecular triplet excimers of covalently linked dimers of naphthalene and quinoxaline.

  7. A generalized Pauli problem and an infinite family of MUB-triplets in dimension 6

    Energy Technology Data Exchange (ETDEWEB)

    Jaming, Philippe [Universite d' Orleans, Faculte des Sciences, MAPMO - Federation Denis Poisson, BP 6759, F 45067 Orleans Cedex 2 (France); Matolcsi, Mate; Weiner, Mihaly [Alfred Renyi Institute of Mathematics, Hungarian Academy of Sciences POB 127 H-1364 Budapest (Hungary); Mora, Peter [BME Department of Analysis, Egry J. u. 1, H-1111 Budapest (Hungary); Szoellosi, Ferenc [Institute of Mathematics and its Applications, Central European University (CEU), H-1051, Nador u. 9., Budapest (Hungary)], E-mail:, E-mail:, E-mail:, E-mail:, E-mail:


    We exhibit an infinite family of triplets of mutually unbiased bases (MUBs) in dimension 6. These triplets involve the Fourier family of Hadamard matrices, F(a, b). However, in the main result of this paper we also prove that for any values of the parameters (a, b), the standard basis and F(a, b) cannot be extended to a MUB-quartet. The main novelty lies in the method of proof which may successfully be applied in the future to prove that the maximal number of MUBs in dimension 6 is three.

  8. $\\mu \\to e \\gamma$ and $\\tau \\to l \\gamma$ decays in the fermion triplet seesaw model

    CERN Document Server

    Abada, A; Bonnet, F; Gavela, M B; Hambye, T


    In the framework of the seesaw models with triplets of fermions, we evaluate the decay rates of $\\mu \\to e \\gamma$ and $\\tau \\to l \\gamma$ transitions. We show that although, due to neutrino mass constraints, those rates are in general expected to be well under the present experimental limits, this is not necessarily always the case. Interestingly enough, the observation of one of those decays in planned experiments would nevertheless contradict bounds stemming from present experimental limits on the $\\mu \\to eee$ and $\\tau \\to 3 l$ decay rates. Such detection of radiative decays would therefore imply that there exist sources of lepton flavour violation not associated to triplet fermions.

  9. Two-step unsymmetrical quantum key distribution protocol using GHZ triplet states

    Institute of Scientific and Technical Information of China (English)

    HUANG Peng; LIU Ye; ZHOU Nan-run; ZENG Gui-hua


    The security, efficiency, transmission distance and error rate are important parameters of a quantum key distribution scheme. In this article, the former two parameters are focused on. To reach high efficiency, an unsymmetrical quantum key distribution scheme that employs Greenberger-Horne-Zeilinger (GHZ) triplet states and dense coding mechanism is proposed, in which a GHZ triplet state can be used to share two bits of classical information. The proposed scheme can be employed in a noisy or lossy quantum channel. In addition, a general approach to security analysis against general individual attacks is presented.

  10. Scattering and Recombination of Two Triplet Excitons in polymer light-emitting diodes

    CERN Document Server

    Meng, Y; Liu, X J; Wang, Y D; An, Z


    The scattering and recombination processes between two triplet excitons in conjugated polymers are investigated by using a nonadiabatic evolution method, based on an extended Su-Schrieffer-Heeger model including interchain interactions. Due to the interchain coupling, the electron and/or hole in the two triplet excitons can exchange. The results show that the recombination induces the formation of singlet excitons, excited polarons and biexcitons. Moreover, we also find the yields of these products, which can contribute to the emission, increase with the interchain coupling strength, in good agreement with results from experiments.

  11. Spin-Selective Generation of Triplet Nitrenes: Olefin Aziridination through Visible-Light Photosensitization of Azidoformates. (United States)

    Scholz, Spencer O; Farney, Elliot P; Kim, Sangyun; Bates, Desiree M; Yoon, Tehshik P


    Azidoformates are interesting potential nitrene precursors, but their direct photochemical activation can result in competitive formation of aziridination and allylic amination products. Herein, we show that visible-light-activated transition-metal complexes can be triplet sensitizers that selectively produce aziridines through the spin-selective photogeneration of triplet nitrenes from azidoformates. This approach enables the aziridination of a wide range of alkenes and the formal oxyamination of enol ethers using the alkene as the limiting reagent. Preparative-scale aziridinations can be easily achieved under continuous-flow conditions.

  12. Charge Transfer and Triplet States in High Efficiency OPV Materials and Devices (United States)

    Dyakonov, Vladimir


    The advantage of using polymers and molecules in electronic devices, such as light-emitting diodes (LED), field-effect transistors (FET) and, more recently, solar cells (SC) is justified by the unique combination of high device performance and processing of the semiconductors used. Power conversion efficiency of nanostructured polymer SC is in the range of 10% on lab scale, making them ready for up-scaling. Efficient charge carrier generation and recombination in SC are strongly related to dissociation of the primary singlet excitons. The dissociation (or charge transfer) process should be very efficient in photovoltaics. The mechanisms governing charge carrier generation, recombination and transport in SC based on the so-called bulk-heterojunctions, i.e. blends of two or more semiconductors with different electron affinities, appear to be very complex, as they imply the presence of the intermediate excited states, neutral and charged ones. Charge transfer states, or polaron pairs, are the intermediate states between free electrons/holes and strongly bound excitons. Interestingly, the mostly efficient OLEDs to date are based on the so-called triplet emitters, which utilize the triplet-triplet annihilation process. In SC, recent investigations indicated that on illumination of the device active layer, not only mobile charges but also triplet states were formed. With respect to triplets, it is unclear how these excited states are generated, via inter-system crossing or via back transfer of the electron from acceptor to donor. Triplet formation may be considered as charge carrier loss channel; however, the fusion of two triplets may lead to a formation of singlet excitons instead. In such case, a generation of charges by utilizing of the so far unused photons will be possible. The fundamental understanding of the processes involving the charge transfer and triplet states and their relation to nanoscale morphology and/or energetics of blends is essential for the

  13. Dynamics of excited-state intramolecular proton transfer reactions in piroxicam. Role of triplet states (United States)

    Cho, Dae Won; Kim, Yong Hee; Yoon, Minjoong; Jeoung, Sae Chae; Kim, Dongho


    The picosecond time-resolved fluorescence and transient absorption behavior of piroxicam at room temperature are reported. The keto tautomer in the excited singlet state ( 1K*) formed via the fast intramolecular proton transfer (≈ 20 ps) is observed. The short-lived (7.5 ns) triplet state of keto tauomer ( 3K*) is generated from 1K * in toluene whereas it is hardly observed in ethanol. Consequently, rapid reverse proton transfer takes place from 3K * to the enol triplet state ( 3E *.

  14. Simulating Entanglement Dynamics of Singlet-Triplet Qubits Coupled to a Classical Transmission Line Resonator (United States)

    Wolfe, Michael; Kestner, Jason

    Electrons confined in lateral quantum dots are promising candidates for scalable quantum bits. Particularly, singlet-triplet qubits can entangle electrostatically and offer long coherence times due to their weak interactions with the environment. However, fast two-qubit operations are challenging. We examine the dynamics of singlet triplet qubits capacitively coupled to a classical transmission line resonator driven near resonance. We numerically simulate the dynamics of the von Neumann entanglement entropy and investigate parameters of the coupling element that optimizes the operation time for the qubit.

  15. A case study of brain morphometry in triplets discordant for Down syndrome. (United States)

    Adeyemi, Elizabeth I; Giedd, Jay N; Lee, Nancy Raitano


    Down syndrome, the most common genetic cause of intellectual disability, offers the opportunity to explore the associations between genetics and both neuroanatomic and neuropsychological phenotypes. This case report summarizes the findings of a neuroimaging and neuropsychology study of two adolescent females with Down syndrome and their same-sex discordant triplet siblings (one from each family; n = 4). Using high-resolution magnetic resonance imaging and surface based morphometric approaches, we offer the first in vivo report of cortical surface area reductions and increases in the thickness of the cortical sheet in youth with Down syndrome relative to their typically developing same-sex triplet siblings.

  16. Preferential Nucleosome Assembly at DNA Triplet Repeats from the Myotonic Dystrophy Gene (United States)

    Wang, Yuh-Hwa; Amirhaeri, Sorour; Kang, Seongman; Wells, Robert D.; Griffith, Jack D.


    The expansion of CTG repeats in DNA occurs in or near genes involved in several human diseases, including myotonic dystrophy and Huntington's disease. Nucleosomes, the basic structural element of chromosomes, consist of 146 base pairs of DNA coiled about an octamer of histone proteins and mediate general transcriptional repression. Electron microscopy was used to examine in vitro the nucleosome assembly of DNA containing repeating CTG triplets. The efficiency of nucleosome formation increased with expanded triplet blocks, suggesting that such blocks may repress transcription through the creation of stable nucleosomes.

  17. Evidence for Triplet Superconductivity in a Superconductor-Ferromagnet Spin Valve (United States)

    Leksin, P. V.; Garif'yanov, N. N.; Garifullin, I. A.; Fominov, Ya. V.; Schumann, J.; Krupskaya, Y.; Kataev, V.; Schmidt, O. G.; Büchner, B.


    We have studied the dependence of the superconducting (SC) transition temperature on the mutual orientation of magnetizations of Fe1 and Fe2 layers in the spin valve system CoOx/Fe1/Cu/Fe2/Pb. We find that this dependence is nonmonotonic when passing from the parallel to the antiparallel case and reveals a distinct minimum near the orthogonal configuration. The analysis of the data in the framework of the SC triplet spin valve theory gives direct evidence for the long-range triplet superconductivity arising due to noncollinearity of the two magnetizations.

  18. A 2-D graphical representation of protein sequences based on nucleotide triplet codons (United States)

    Bai, Fenglan; Wang, Tianming


    Graphical representation of DNA provides a simple way of viewing, sorting and comparing various gene structures. A 2-D graphical representation of protein sequences based on nucleotide triplet codons has been derived for similarity analysis of protein sequences. This approach is based on a graphical representation of triplets of DNA in which the interior of the left half plane of the complex plane is used to accommodate 64 sites for the 64 codons. We associate a directed curve, numerical value, or matrix with a protein as a descriptor. The approach is illustrated on the Homo sapiens X-linked nuclear protein (ATRX) gene.

  19. Non-adiabatic and intersystem crossing dynamics in SO2. II. The role of triplet states in the bound state dynamics studied by surface-hopping simulations. (United States)

    Mai, Sebastian; Marquetand, Philipp; González, Leticia


    The importance of triplet states in the photorelaxation dynamics of SO2 is studied by mixed quantum-classical dynamics simulations. Using the SHARC method, standing for Surface Hopping including ARbitrary Couplings, intersystem crossing (ISC) processes caused by spin-orbit coupling are found occurring on an ultrafast time scale (few 100 fs) and thus competing with internal conversion. While in the singlet-only dynamics only oscillatory population transfer between the (1)B1 and (1)A2 states is observed, in the dynamics including singlet and triplet states we find additionally continuous ISC to the (3)B2 state and to a smaller extent to the (3)B1/(3)A2 coupled states. The populations obtained from the dynamics are discussed with respect to the overall nuclear motion and in the light of recent TRPEPICO studies [I. Wilkinson, A. E. Boguslavskiy, J. Mikosch, D. M. Villeneuve, H.-J. Wörner, M. Spanner, S. Patchkovskii, and A. Stolow, "Excited state dynamics in SO2. I. Bound state relaxation studied by time-resolved photoelectron-photoion coincidence spectroscopy," J. Chem. Phys. 140, 204301 (2014)].

  20. Mechanism of deactivation of triplet-excited riboflavin by ascorbate, carotenoids, and tocopherols in homogeneous and heterogeneous aqueous food model systems. (United States)

    Cardoso, Daniel R; Olsen, Karsten; Skibsted, Leif H


    Tocopherols (alpha, beta, gamma, and delta) and Trolox were found to deactivate triplet-excited riboflavin in homogeneous aqueous solution (7:3 v/v tert-butanol/water) with second-order reaction rates close to diffusion control [k2 between 4.8 x 10(8) (delta-tocopherol) and 6.2 x 10(8) L mol(-1) s(-1) (Trolox) at 24.0 +/- 0.2 degrees C] as determined by laser flash photolysis transient absorption spectroscopy. In aqueous buffer (pH 6.4) the rate constant for Trolox was 2.6 x 10(9) L mol(-1) s1 and comparable to the rate constant found for ascorbate (2.0 x 10(9) L mol(-1) s(-1)). The deactivation rate constant was found to be inferior in heterogeneous systems as shown for alpha-tocopherol and Trolox in aqueous Tween-20 emulsion (approximately by a factor of 4 compared to 7:3 v/v tert-butanol/water). Neither beta-carotene (7:3 v/v tert-butanol/water and Tween-20 emulsion), lycopene (7:3 v/v tert-butanol/water), nor crocin (aqueous buffer at pH 6.4, 7:3 v/v tert-butanol/water, and Tween-20 emulsion) showed any quenching on the triplet excited state of riboflavin. Therefore, all carotenoids seem to reduce the formation of triplet-excited riboflavin through an inner-filter effect. Activation parameters were based on the temperature dependence of the triplet-excited deactivation between 15 and 35 degrees C, and the isokinetic behavior, which was found to include purine derivatives previously studied, confirms a common deactivation mechanism with a bimolecular diffusion-controlled encounter with electron (or hydrogen atom) transfer as rate-determining step. DeltaH for deactivation by ascorbic acid, Trolox, and homologue tocopherols (ranging from 18 kJ mol(-1) for Trolox in Tween-20 emulsion to 184 kJ mol(-1) for ascorbic acid in aqueous buffer at pH 6.4) showed a linear dependence on DeltaS (ranging from -19 J mol(-1) K(-1) for Trolox in aqueous buffer at pH 6.4 to +550 J mol(-1) K(-1) for ascorbic acid in aqueous buffer pH 6.4). Among photooxidation products from the

  1. A practical O(n log2 i>n>) time algorithm for computing the triplet distance on binary trees

    DEFF Research Database (Denmark)

    Sand, Andreas; Brodal, Gerth Stølting; Fagerberg, Rolf;


    The triplet distance is a distance measure that compares two rooted trees on the same set of leaves by enumerating all sub-sets of three leaves and counting how often the induced topologies of the tree are equal or different. We present an algorithm that computes the triplet distance between two ...

  2. Conformational instability of the lowest triplet state of the benzene nucleus: II. p-Xylene, the influence of substituents

    NARCIS (Netherlands)

    J.H. van der Waals; M.C. van Hemert; W.J. Buma


    A calculation of the potential-energy surface of the lowest triplet state of p-xylene as a function of the S8(,) distortion coordinate of the benzene skeleton has been made to learn more about the influence of substituents on the vibronically induced distortion of benzene in its metastable triplet s

  3. A smart tailor-made G-clip reporter for sensitive detection of G-triplet-containing sequences. (United States)

    Cai, Liang-Yuan; Nie, Ji; Zhang, Yi-Wei; Zhang, Fang-Ting; Zhou, Ying-Lin; Zhang, Xin-Xiang


    Taking advantage of the intrinsic characteristics of G-triplet-containing sequences, a pioneering tailor-made clip-like reporter containing three-fourths of a G-quadruplex is established. The reporter can clip the G triplet in the target sequence through a recognition process to form a complete G-quadruplex structure.

  4. Etude par R.P.E. des excitons triplets dans le dimethyl-1,5 nortropinone nitroxyde (United States)

    Gloux, J.; Genoud, F.; Decorps, M.

    Dimerization of 1,5 dimethyl-nortropinone nitroxide in the solid state is investigated by E.S.R. spectroscopy. In this compound, the arrangement of the two neighbouring NO fragments is not rectangular. The E.S.R. spectra of the single crystal are characteristic of a thermally accessible triplet state. The absence of resolved hyperfine structure, the observation of only one pair of E.S.R. lines despite the existence of the two translationally inequivalent dimers A and B and the anisotropy of linewidth show that the excitations move rapidly from one dimer to the other. This motion occurs at a frequency sufficient to average the dipolar tensors DA and DB of the two dimers A and B. Thus, the spectra are well described by the spin hamiltonian tMPH0251_images in which D is the average dipolar tensor. The zero-field splittings parameters are: tMPH0251_images The hopping rate between translationally inequivalent dimers is obtained from the study of the anisotropic linewidth; this rate is not activated and is about 3 × 108 Hz.

  5. An optical--near-IR study of a triplet of super star clusters in the starburst core of M82

    CERN Document Server

    Westmoquette, M S; Smith, L J; Seth, A C; Gallagher, J S; O'Connell, R W; Ryon, J E; Silich, S; Mayya, Y D; Munoz-Tunon, C; Gonzalez, D Rosa


    We present HST/STIS optical and Gemini/NIFS near-IR IFU spectroscopy, and archival HST imaging of the triplet of super star clusters (A1, A2 and A3) in the core of the M82 starburst. Using model fits to the STIS spectra, and the weakness of red supergiant CO absorption features (appearing at ~6 Myr) in the NIFS H-band spectra, the ages of A2 and A3 are $4.5\\pm1.0$~Myr. A1 has strong CO bands, consistent with our previously determined age of $6.4\\pm0.5$~Myr. The photometric masses of the three clusters are 4--$7\\times10^5$~\\Msol, and their sizes are $R_{\\rm eff}=159$, 104, 59~mas ($\\sim$2.8, 1.8, 1.0~pc) for A1,2 and 3. The STIS spectra yielded radial velocities of $320\\pm2$, $330\\pm6$, and $336\\pm5$~\\kms\\ for A1,2, and 3, placing them at the eastern end of the $x_2$ orbits of M82's bar. Clusters A2 and A3 are in high density (800--1000~\\cmt) environments, and like A1, are surrounded by compact H\\two\\ regions. We suggest the winds from A2 and A3 have stalled, as in A1, due to the high ISM ambient pressure. We ...

  6. Imaging spectrometer trade studies: a detailed comparison of the Offner-Chrisp and reflective triplet optical design forms (United States)

    Cook, Lacy G.; Silny, John F.


    High quality imaging spectroscopy data is useful for both military and civilian applications. Current state-of-the-art imaging spectrometers typically rely on the Offner-Chrisp (OC) optical form. Making use of a spherically concentric, axially symmetric, and telecentric design, the OC imaging spectrometer provides excellent spectral-spatial uniformity but with many regrets: (1) no real-entrance pupil, (2) relatively slow optical speeds, (3) required convex diffraction grating, (4) narrow field-of-view, and (5) limited scalability. Recently, the Raytheon patented Reflective Triplet (RT) optical design form has produced extremely large format imaging spectrometers of exceptional quality. The RT optical design provides spectral-spatial uniformity comparable to the OC form, but with a number of advantages: (1) extremely large fields-of-view, (2) faster optical speeds, (3) a real-entrance pupil for optimal cold shielding and calibration, (4) use of either a prism or flat diffraction grating operating in collimated space (with an option for both simultaneously in a 2- channel device), and (5) extremely wide spectral range using common reflective optics and multiple focal plane arrays, dispersive elements, and entrance slits. This paper presents a number of detailed designs exemplifying the differences between the OC and RT forms.

  7. Thickness dependence of the triplet spin-valve effect in superconductor-ferromagnet heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Lenk, Daniel; Zdravkov, Vladimir I.; Kehrle, Jan; Obermeier, Guenther; Krug von Nidda, Hans-Albrecht; Mueller, Claus; Horn, Siegfried; Tidecks, Reinhard [Institut fuer Physik, Universitaet Augsburg (Germany); Morari, Roman [Institut fuer Physik, Universitaet Augsburg (Germany); D. Ghitsu Institute of Electronic Engineering and Nanotechnologies ASM, Kishinev (Moldova, Republic of); Sidorenko, Anatolie S. [D. Ghitsu Institute of Electronic Engineering and Nanotechnologies ASM, Kishinev (Moldova, Republic of); Tagirov, Lenar [Solid State Physics Department, Kazan Federal University (Russian Federation)


    We investigated the triplet spin-valve effect in nanoscale layered S/F{sub 1}/N/F{sub 2}/AF heterostructures with varying F{sub 1}-layer thickness (where S=Nb is a singlet superconducting, F{sub 1}=Cu{sub 41}Ni{sub 59} and F{sub 2}=Co a ferromagnetic, and N a normal-conducting, non-magnetic layer). The theory predicts a long-range, odd-in-frequency triplet component of superconductivity at non-collinear alignment of the magnetizations of F{sub 1} and F{sub 2}. This triplet component exhausts the singlet state and, thus, lowers the superconducting transition temperature, T{sub c}, yielding a global minimum of T{sub c} close to the perpendicular mutual orientations of the magnetizations. We found an oscillating decay of T{sub c} suppression, due to the generation of the triplet component, with increasing F{sub 1} layer thickness, which we discuss in the framework of recent theories.

  8. How disorder controls the kinetics of triplet charge recombination in semiconducting organic polymer photovoltaics. (United States)

    Bittner, Eric R; Lankevich, Vladimir; Gélinas, Simon; Rao, Akshay; Ginger, David A; Friend, Richard H


    Recent experiments by Rao et al. (Nature, 2013, 500, 435-439) indicate that recombination of triplet charge-separated states is suppressed in organic polymer-fullerene based bulk-heterojunction (BHJ) photovoltaic cells exhibiting a high degree of crystallinity in the fullerene phase relative to systems with more disorder. In this paper, we use a series of Frenkel-exciton lattice models to rationalize these results in terms of wave-function localization, interface geometry, and density of states. In one-dimensional co-linear and co-facial models of the interface, increasing local energetic disorder in one phase localizes the interfacial triplet charge-transfer ((3)CT) states and increases the rate at which these states relax to form lower-energy triplet excitons. In two dimensional BHJ models, energetic disorder within the fullerene phase plays little role in further localizing states pinned to the interface. However, inhomogeneous broadening introduces strong coupling between the interfacial (3)CT and nearby fullerene triplet excitons and can enhance the decay of these states in systems with higher degrees of energetic disorder.

  9. Maternal and Fetal Outcomes of Triplet Gestation in a Tertiary Hospital in Oman

    Directory of Open Access Journals (Sweden)

    Maryam Al-Shukri


    Full Text Available Objectives: The aim of this study was to describe the fetal and maternal outcomes of triplet gestation and to report on the maternal characteristics of those pregnancies in a tertiary care centre in Oman. Methods: A retrospective study was undertaken of all triplet pregnancies delivered at Sultan Qaboos University Hospital, Muscat, Oman, between January 2009 and December 2011. Results: Over the three-year study period, there were 9,140 deliveries. Of these, there were 18 triplet pregnancies, giving a frequency of 0.2%. The mean gestational age at delivery was 31.0 ± 3.0 weeks, and the mean birth weight was 1,594 ± 460 g. The most common maternal complications were preterm labour in 13 pregnancies (72.2%, gestational diabetes in 7 (39% and gestational hypertension in 5 (28%. Of the total deliveries, there were 54 neonates. Neonatal complications among these included hyaline membrane disease in 25 neonates (46%, hyperbilirubinaemia in 24 (43%, sepsis in 18 (33% and anaemia in 8 (15%. The perinatal mortality rate was 55 per 1,000 births. Conclusion: The maternal and neonatal outcomes of triplet pregnancies were similar to those reported in other studies.

  10. Photoprotection and triplet energy transfer in higher plants: the role of electronic and nuclear fluctuations. (United States)

    Cupellini, Lorenzo; Jurinovich, Sandro; Prandi, Ingrid G; Caprasecca, Stefano; Mennucci, Benedetta


    Photosynthetic organisms employ several photoprotection strategies to avoid damage due to the excess energy in high light conditions. Among these, quenching of triplet chlorophylls by neighboring carotenoids (Cars) is fundamental in preventing the formation of singlet oxygen. Cars are able to accept the triplets from chlorophylls by triplet energy transfer (TET). We have here studied TET rates in CP29, a minor light-harvesting complex (LHC) of the Photosystem II in plants. A fully atomistic strategy combining classical molecular dynamics of the LHC in its natural environment with a hybrid time-dependent density functional theory/polarizable MM description of the TET is used. We find that the structural fluctuations of the pigment-protein complex can largely enhance the transfer rates with respect to those predicted using the crystal structure, reducing the triplet quenching times in the subnanosecond scale. These findings add a new perspective for the interpretation of the photoprotection function and its relation with structural motions of the LHC.

  11. Three-Dimensional Triplet Tracking for LHC and Future High Rate Experiments

    CERN Document Server

    Schöning, Andre


    The hit combinatorial problem is a main challenge for track reconstruction and triggering at high rate experiments. At hadron colliders the dominant fraction of hits is due to low momentum tracks for which multiple scattering (MS) effects dominate the hit resolution. MS is also the dominating source for hit confusion and track uncertainties in low energy precision experiments. In all such environments, where MS dominates, track reconstruction and fitting can be largely simplified by using three-dimensional (3D) hit-triplets as provided by pixel detectors. This simplification is possible since track uncertainties are solely determined by MS if high precision spatial information is provided. Fitting of hit-triplets is especially simple for tracking detectors in solenoidal magnetic fields. The over-constrained 3D-triplet method provides a complete set of track parameters and is robust against fake hit combinations. The triplet method is ideally suited for pixel detectors where hits can be treated as 3D-space poi...

  12. Conformational instability of the lowest triplet state of the benzene nucleus: I. The unsubstituted molecule

    NARCIS (Netherlands)

    J.H. van der Waals; M.C. van Hemert; W.J. Buma


    Experiments on benzene have established that its lowest triplet state (3B1u) is conformationally unstable owing to vibronic coupling with the next higher state (3E1u). This instability was found to be critically dependent on the influence of a crystal field. An analogous vibronic coupling is to be e

  13. Ab initio calculations on the structure of pyridine in its lowest triplet state

    NARCIS (Netherlands)

    Buma, W.J.; Groenen, E.J.J.; Schmidt, J.


    Recently we have experimentally shown that pyridine-d5, as a guest in a single crystal of benzene-d6, adopts a boatlike structure upon excitation into the lowest triplet state T0. Here MRDCI ab initio calculations are presented that reveal that the observed nonplanarity of the molecule is not caused

  14. Spectrally tunable mollow triplet emission from a coherently excited quantum dot in a microcavity

    DEFF Research Database (Denmark)

    Ulrich, Sven M.; Ates, Serkan; Reitzenstein, Stephan;


    with large Rabi splittings of j~­j » 60¹eV have been observed. Laser detuning-dependent series revealed the pronounced asymmetry of the emission triplet as predicted by theory. From our data, an electrical dipole moment of ¹ » 17:8§0:5 Debye could be derived for the excitonic state....

  15. Triplet exciplexes in reactions of electronically excited chloranil with unsatuated heterocyclic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Petroshenko, K.B.; Frolov, Y.L.; Gorshkov, A.G.; Osipov, S.P.; Turchaninov, V.K.; Vokin, A.I.


    In the system indole + chloranil + dioxane the formation has been demonstrated of a triplet exciplex with complete charge transfer and a hydrogen bond between the components. The presence of a hydrogen bond in the dissociative state results in a decrease in the yield of free ion-radicals.

  16. Triplet state dynamics of chlorophylls in photosynthetic reaction centers and model systems.

    NARCIS (Netherlands)

    Wijk, van F.G.H.


    In this work the temperature dependence of the lineshape, and more specifically, the electron spin polarization pattern of the Δm = ±1 triplet EPR (Electron Paramagnetic Resonance) spectra from several photosynthetic purple bacteria has been investigated.In Chapter I a general introduction is presen

  17. Isolation of proximity-induced triplet pairing channel in a superconductor/ferromagnet spin valve (United States)

    Leksin, P. V.; Garif'yanov, N. N.; Kamashev, A. A.; Validov, A. A.; Fominov, Ya. V.; Schumann, J.; Kataev, V.; Thomas, J.; Büchner, B.; Garifullin, I. A.


    We have studied the proximity-induced superconducting triplet pairing in CoOx/Py1/Cu/Py2/Cu/Pb spin-valve structure (where Py = Ni0.81Fe0.19 ). By optimizing the parameters of this structure we found a triplet channel assisted full switching between the normal and superconducting states. To observe an "isolated" triplet spin-valve effect we exploited the oscillatory feature of the magnitude of the ordinary spin-valve effect Δ Tc in the dependence of the Py2-layer thickness dP y 2. We determined the value of dP y 2 at which Δ Tc caused by the ordinary spin-valve effect (the difference in the superconducting transition temperature Tc between the antiparallel and parallel mutual orientation of magnetizations of the Py1 and Py2 layers) is suppressed. For such a sample a "pure" triplet spin-valve effect which causes the minimum in Tc at the orthogonal configuration of magnetizations has been observed.

  18. Computational determination of the dominant triplet population mechanism in photoexcited benzophenone

    NARCIS (Netherlands)

    Sergentu, Dumitru-Claudiu; Maurice, Remi; Havenith, Remco W. A.; Broer, Ria; Roca-Sanjuan, Daniel


    In benzophenone, intersystem crossing occurs efficiently between the S-1(n pi(star)) state and the T-1 state of dominant n pi(star) character, leading to excited triplet states after photoexcitation. The transition mechanism between S-1(n pi(star)) and T-1 is still a matter of debate, despite severa

  19. Quenching excited triplet C{sub 60} fullerene by tetracyanoethylene in benzonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Nadtochenko, V.A.; Denisov, N.N.; Rubtsov, I.V.; Lobach, A.S.; Moravsky, A.P. [Institute of Chemical Physics in Chernogolovka, Moscow (Russian Federation)


    The main photophysical properties of C{sub 60} fullerene: The absorption spectra of excited singlet C{sub 60}, the inter-combinational conversion time, the quantum yield of triplet C{sub 60}, the triplet-triplet absorption spectra, and the channels and rate constants of the deactivation of triplet C{sub 60} have been established. The photochemical properties of C{sub 60} fullerene have been investigated to a lesser degree. C{sub 60} is known to be readily reduced (E{sub 1/2} = {minus}0.4 in relation to Ag/Ag{sup +}), in particular, photochemically. For example, photoexcitation of charge-transfer complexes of C{sub 60} with amines gives the radical anion C{sup {minus}}{sub 60} which is also formed in reactions of photoexcited C{sub 60} fullerene. The formation of the radical cation C{sup +}{sub 60} under the action of light has been detected in the reaction with colloidal TiO{sub 2}. The radical ion C{sup +}{sub 60} has been obtained in a homogeneous photochemical process: the reaction of unexcited C{sub 60} with excited singlet N-methylacridinium hexafluorophosphate or with the biphenyl radical cation generated in the reaction with excited singlet N-methylacridinium hexafluorophosphate. The formation of C{sup +}{sub 60} with an electron acceptor in a homogeneous process has not so far been observed. The purpose of this work has been to study the quenching of triplet {sup 3}C{sub 60} with an electron acceptor, tetracyanoethylene (TCNE), which is known to oxidize unsaturated or aromatic hydrocarbons in photochemical reactions.

  20. Terahertz spectroscopy

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd


    In this presentation I will review methods for spectroscopy in the THz range, with special emphasis on the practical implementation of the technique known ad THz time-domain spectroscopy (THz-TDS). THz-TDS has revived the old field of far-infrared spectroscopy, and enabled a wealth of new...

  1. OLEDs under high current densities. Transient electroluminescence turn-on peaks and singlet-triplet quenching

    Energy Technology Data Exchange (ETDEWEB)

    Kasemann, Daniel


    This work focuses on a better understanding of the behavior of organic light emitting devices (OLEDs) under intense electrical excitation. Attaining high exciton densities in organic semiconductors by electrical excitation is of special interest for the field of organic semiconductor lasers (OSLs). In these devices, the high singlet exciton density needed in the active layer to obtain population inversion is easily created by pulsed optical pumping, but direct electrical pumping has not been achieved yet. First, the steps necessary to achieve stable high current densities in organic semiconductors are discussed. After determining the optimal excitation scheme using single p-doped transport layers, the device complexity is increased up to full p-i-n OLEDs with their power dependent emission spectra. For this purpose, two exemplary emitter systems are chosen: the fluorescent laser dye 4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran (DCM) doped into Aluminum(III)bis (2-methyl-8-quinolinato)-4-phenylphenolate (Alq{sub 3}) and the efficient phosphorescent emitter system N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine (alpha-NPD) doped by Iridium(III) bis(2-methyl-dibenzo[f,h]quinoxaline)(acetylacetonate) (Ir(MDQ){sub 2}(acac)). For pulsed excitation using 50 ns pulses and a repetition rate of 1 kHz, single 100 nm thin p- and n-doped transport layers sustain current densities of over 6 kA/cm{sup 2}. While the maximum current density decreases with increasing device thickness, the full OLEDs still sustain current densities beyond 800 A/cm{sup 2} and exhibit a continuously increasing emission intensity with increasing input power. Next, the time-resolved emission behavior of the singlet and triplet emitter device at high excitation densities is analyzed on the nanosecond scale. Here, the peak emission intensity of the phosphorescent emitter system is found to be more than eight times lower than for the singlet emitter system at comparable current

  2. On the hyperfine structure of the triplet $n^{3}S-$states of the four-electron atoms and ions

    CERN Document Server

    Frolov, Alexei M


    Hyperfine structures of the triplet $n^3S-$states in the four-electron Be-atom(s) and Be-like ions are considered. It is shown that to determine the hyperfine structure splitting in such atomic systems one needs to know the triplet electron density at the central atomic nucleus $\\rho_T(0)$. We have developed the procedure which allows allows one to determine the triplet electron density $\\rho_T(0)$ for arbitrary four-electron atoms and ions.

  3. Progress in dynamic study on the triplet excited states and radical ions of DNA and its components

    Institute of Scientific and Technical Information of China (English)

    宋钦华; 林念芸; 姚思德; 张加山


    Progress in dynamic study on the triplet excited states and radical ions of DNA and its components is reviewed. It has been found that acetone is the only effective sensitizer for the study of the triplet excited states of DNA components. The transient absorption spectrum of guanyl radical cation resulting from the interaction of triplet acetone and DNA was observed directly, and the original evidence for selective damage of DNA by excited photosensitizer was obtained for the first time, which offered a new pathway for obtaining the main transient species of selective damage of DNA by photonucleases and illustrating initial oxidation mechanism of DNA via electron transfer.

  4. Thickness dependence of the triplet spin-valve effect in superconductor–ferromagnet–ferromagnet heterostructures (United States)

    Zdravkov, Vladimir I; Kehrle, Jan-Michael; Obermeier, Günter; Ullrich, Aladin; Morari, Roman; Krug von Nidda, Hans-Albrecht; Müller, Claus; Kupriyanov, Mikhail Yu; Sidorenko, Anatolie S; Horn, Siegfried; Deminov, Rafael G; Tagirov, Lenar R; Tidecks, Reinhard


    Summary Background: In nanoscale layered S/F1/N/F2/AF heterostructures, the generation of a long-range, odd-in-frequency spin-projection one triplet component of superconductivity, arising at non-collinear alignment of the magnetizations of F1 and F2, exhausts the singlet state. This yields the possibility of a global minimum of the superconducting transition temperature T c, i.e., a superconducting triplet spin-valve effect, around mutually perpendicular alignment. Results: The superconducting triplet spin valve is realized with S = Nb a singlet superconductor, F1 = Cu41Ni59 and F2 = Co ferromagnetic metals, AF = CoOx an antiferromagnetic oxide, and N = nc-Nb a normal conducting (nc) non-magnetic metal, which serves to decouple F1 and F2. The non-collinear alignment of the magnetizations is obtained by applying an external magnetic field parallel to the layers of the heterostructure and exploiting the intrinsic perpendicular easy-axis of the magnetization of the Cu41Ni59 thin film in conjunction with the exchange bias between CoOx and Co. The magnetic configurations are confirmed by superconducting quantum interference device (SQUID) magnetic moment measurements. The triplet spin-valve effect has been investigated for different layer thicknesses, d F1, of F1 and was found to decay with increasing d F1. The data is described by an empirical model and, moreover, by calculations using the microscopic theory. Conclusion: The long-range triplet component of superconducting pairing is generated from the singlet component mainly at the N/F2 interface, where the amplitude of the singlet component is suppressed exponentially with increasing distance d F1. The decay length of the empirical model is found to be comparable to twice the electron mean free path of F1 and, thus, to the decay length of the singlet component in F1. Moreover, the obtained data is in qualitative agreement with the microscopic theory, which, however, predicts a (not investigated) breakdown of the

  5. Thickness dependence of the triplet spin-valve effect in superconductor–ferromagnet–ferromagnet heterostructures

    Directory of Open Access Journals (Sweden)

    Daniel Lenk


    Full Text Available Background: In nanoscale layered S/F1/N/F2/AF heterostructures, the generation of a long-range, odd-in-frequency spin-projection one triplet component of superconductivity, arising at non-collinear alignment of the magnetizations of F1 and F2, exhausts the singlet state. This yields the possibility of a global minimum of the superconducting transition temperature Tc, i.e., a superconducting triplet spin-valve effect, around mutually perpendicular alignment.Results: The superconducting triplet spin valve is realized with S = Nb a singlet superconductor, F1 = Cu41Ni59 and F2 = Co ferromagnetic metals, AF = CoOx an antiferromagnetic oxide, and N = nc-Nb a normal conducting (nc non-magnetic metal, which serves to decouple F1 and F2. The non-collinear alignment of the magnetizations is obtained by applying an external magnetic field parallel to the layers of the heterostructure and exploiting the intrinsic perpendicular easy-axis of the magnetization of the Cu41Ni59 thin film in conjunction with the exchange bias between CoOx and Co. The magnetic configurations are confirmed by superconducting quantum interference device (SQUID magnetic moment measurements. The triplet spin-valve effect has been investigated for different layer thicknesses, dF1, of F1 and was found to decay with increasing dF1. The data is described by an empirical model and, moreover, by calculations using the microscopic theory.Conclusion: The long-range triplet component of superconducting pairing is generated from the singlet component mainly at the N/F2 interface, where the amplitude of the singlet component is suppressed exponentially with increasing distance dF1. The decay length of the empirical model is found to be comparable to twice the electron mean free path of F1 and, thus, to the decay length of the singlet component in F1. Moreover, the obtained data is in qualitative agreement with the microscopic theory, which, however, predicts a (not investigated breakdown of the

  6. A triplet-triplet annihilation based up-conversion process investigated in homogeneous solutions and oil-in-water microemulsions of a surfactant. (United States)

    Penconi, Marta; Gentili, Pier Luigi; Massaro, Giuseppina; Elisei, Fausto; Ortica, Fausto


    The triplet-triplet annihilation based up-conversion process, involving a platinum octaethyl-porphyrin (PtOEP) as a sensitizer and tetraphenyl-pyrene (TPPy) as an emitter, has been investigated in homogeneous solutions of toluene, bromobenzene and anisole, and oil-in-water microemulsions of the TX-100 surfactant, where toluene constitutes the non-polar phase. In homogeneous solutions, the highest up-conversion quantum yield (of the order of 20%) has been achieved in toluene, being the solvent that has the lowest viscosity among those explored. The up-conversion emission from the PtOEP-TPPy pair has been then investigated in a toluene based oil-in-water microemulsion at three different concentrations of the solutes, showing quantum yields up to the order of 1%, under the same irradiation conditions, but different deoxygenating procedures. The results herein reported might represent a good starting point for a future investigation in microheterogeneous systems. An optimization of the microemulsion composition, in terms of surfactant, co-surfactant and toluene concentrations, could allow us to increase the sensitizer and emitter concentrations and set up the best operative conditions to obtain even higher up-conversion efficiencies.

  7. TripNet: A Method for Constructing Phylogenetic Networks from Triplets

    CERN Document Server

    Tusserkani, Ruzbeh; Poormohammadi, Hadi; Azadi, Azin


    We present TripNet, a method for constructing phylogenetic networks from triplets. We will present the motivations behind our approach and its theoretical and empirical justification. To demonstrate the accuracy and efficiency of TripNet, we performed two simulations and also applied the method to five published data sets: Kreitman's data, a set of triplets from real yeast data obtained from the Fungal Biodiversity Center in Utrecht, a collection of 110 highly recombinant Salmonella multi-locus sequence typing sequences, and nrDNA ITS and cpDNA JSA sequence data of New Zealand alpine buttercups of Ranunculus sect. Pseudadonis. Finally, we compare our results with those already obtained by other authors using alternative methods. TripNet, data sets, and supplementary files are freely available for download at (

  8. Triplet p-wave pairing correlation in low-doped zigzag graphene nanoribbons (United States)

    Ma, Tianxing; Yang, Fan; Huang, Zhongbing; Lin, Hai-Qing


    We reveal an edge spin triplet p–wave superconducting pairing correlation in slightly doped zigzag graphene nanoribbons. By employing a method that combines random-phase approximation, the finite-temperature determinant quantum Monte Carlo approach, and the ground-state constrained-path quantum Monte Carlo method, it is shown that such a spin-triplet pairing is mediated by the ferromagnetic fluctuations caused by the flat band at the edge. The spin susceptibility and effective pairing interactions at the edge strongly increase as the on-site Coulomb interaction increases, indicating the importance of electron-electron correlations. It is also found that the doping-dependent ground-state p-wave pairing correlation bears some similarity to the famous superconducting dome in the phase diagram of a high-temperature superconductor, while the spin correlation at the edge is weakened as the system is doped away from half filling. PMID:28186185

  9. Photopolymer material sensitized by xanthene dyes for holographic recording using forbidden singlet-triplet electronic transitions (United States)

    Shelkovnikov, Vladimir; Vasiljev, Evgeny; Russkih, Vladimlen; Berezhnaya, Viktoria


    A new holographic photopolymer material is developed. The photopolymer material is sensitized by dyes of xanthene and thioxanthene series which contain iodine and bromine heavy atoms. Holographic recording was carried out during excitation of forbidden singlet-triplet electron transitions of dyes. Thioerythrosin triethylammonium was identified as the most effective sensitizer among a number of tested dyes. The spectral absorption area of the singlet-triplet electronic transition of the dye is conveyed in the red spectral range from 600 to 700 nm. The sensitivity of the photopolymer material to radiation with 633 nm wavelength is 180 mJ cm-2. Optimization of concentration of the main components of the photopolymer compositions was carried out in order to achieve maximum efficiency of holographic recording.

  10. Triplet FFLO superconductivity in the doped Kitaev-Heisenberg honeycomb model (United States)

    Liu, Tianhan; Repellin, Cécile; Douçot, Benoît; Regnault, Nicolas; Le Hur, Karyn


    We provide analytical and numerical evidence of spin-triplet Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconductivity in the itinerant Kitaev-Heisenberg model (antiferromagnetic Kitaev coupling and ferromagnetic Heisenberg coupling) on the honeycomb lattice around quarter filling. The strong spin-orbit coupling in our model leads to the emergence of six inversion symmetry centers for the Fermi surface at nonzero momenta in the first Brillouin zone. We show how the Cooper pairs condense into these nontrivial momenta, causing spatial modulation of the superconducting order parameter. Applying a Ginzburg-Landau expansion analysis, we find that the superconductivity has three separated degenerate ground states with three different spin-triplet pairings. Exact diagonalizations on finite clusters support this picture while ruling out a spin (charge) density wave.

  11. Quench Limit Calculation for Steady State Heat Deposits in LHC Inner Triplet Magnets

    CERN Document Server

    Cerutti, F; Esposito, L S; Siemko, A; Bocian, D


    In hadron colliders such as the LHC, the energy deposited in the superconductors by the particles lost from the beams or coming from the collision debris may provoke quenches detrimental to the accelerator operation. A Network Model is used to simulate the thermodynamic behavior of the superconducting magnets. In previous papers the validations of network model with measurements performed in the CERN and Fermilab magnet test facilities were presented. This model was subsequently used for thermal analysis of the current LHC inner triplet quadrupole magnets for beam energy of 3.5 TeV and 7.0 TeV. The detailed study of helium cooling channels efficiency for energy deposits simulated with FLUKA was performed. The expected LHC inner triplet magnets quench limit is presented.

  12. Triplet repeat DNA structures and human genetic disease: dynamic mutations from dynamic DNA

    Indian Academy of Sciences (India)

    Richard R Sinden; Vladimir N Potaman; Elena A Oussatcheva; Christopher E Pearson; Yuri L Lyubchenko; Luda S Shlyakhtenko


    Fourteen genetic neurodegenerative diseases and three fragile sites have been associated with the expansion of (CTG)n•(CAG)n, (CGG)n•(CCG)n, or (GAA)n•(TTC)n repeat tracts. Different models have been proposed for the expansion of triplet repeats, most of which presume the formation of alternative DNA structures in repeat tracts. One of the most likely structures, slipped strand DNA, may stably and reproducibly form within triplet repeat sequences. The propensity to form slipped strand DNA is proportional to the length and homogeneity of the repeat tract. The remarkable stability of slipped strand DNA may, in part, be due to loop-loop interactions facilitated by the sequence complementarity of the loops and the dynamic structure of three-way junctions formed at the loop-outs.

  13. Triplet p-wave pairing correlation in low-doped zigzag graphene nanoribbons (United States)

    Ma, Tianxing; Yang, Fan; Huang, Zhongbing; Lin, Hai-Qing


    We reveal an edge spin triplet p–wave superconducting pairing correlation in slightly doped zigzag graphene nanoribbons. By employing a method that combines random-phase approximation, the finite-temperature determinant quantum Monte Carlo approach, and the ground-state constrained-path quantum Monte Carlo method, it is shown that such a spin-triplet pairing is mediated by the ferromagnetic fluctuations caused by the flat band at the edge. The spin susceptibility and effective pairing interactions at the edge strongly increase as the on-site Coulomb interaction increases, indicating the importance of electron-electron correlations. It is also found that the doping-dependent ground-state p-wave pairing correlation bears some similarity to the famous superconducting dome in the phase diagram of a high-temperature superconductor, while the spin correlation at the edge is weakened as the system is doped away from half filling.

  14. Effect of isoscalar spin-triplet pairings on spin-isospin responses in $sd-$ shell nuclei

    CERN Document Server

    Sagawa, H; Sasano, M


    The spin magnetic dipole transitions and the neutron-proton spin-spin correlations in $sd-$shell even-even nuclei with $N=Z$ are investigated using shell model wave functions. The isoscalar spin-triplet pairing correlation provides a substantial quenching effect on the spin magnetic dipole transitions, especially the isovector (IV) ones. Consequently, an enhanced isoscalar spin-triplet pairing interaction influences the proton-neutron spin-spin correlation deduced from the difference between the isoscalar (IS) and the IV sum rule strengths. The effect of the $\\Delta$ ($\\Delta_{33}$ resonance)-hole coupling is examined in the IV spin transition and the spin-spin correlations of the ground states.

  15. Proximity effects in superconducting triplet spin-valve F2/F1/S

    Energy Technology Data Exchange (ETDEWEB)

    Deminov, R.G., E-mail: [Institute of Physics, Kazan Federal University, Kazan 420008 (Russian Federation); Tagirov, L.R. [Institute of Physics, Kazan Federal University, Kazan 420008 (Russian Federation); Institut für Physik, Universität Augsburg, Augsburg D-86159 (Germany); Gaifullin, R.R. [Institute of Physics, Kazan Federal University, Kazan 420008 (Russian Federation); Karminskaya, T.Yu.; Kupriyanov, M.Yu. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119992 (Russian Federation); Fominov, Ya.V. [Landau Institute for Theoretical Physics RAS, Moscow 119334 (Russian Federation); Golubov, A.A. [Faculty of Science and Technology and MESA+ Institute of Nanotechnology, University of Twente, P.O. Box 217, Enschede 7500 AE (Netherlands)


    We investigate the critical temperature T{sub c} of F2/F1/S trilayers (Fi is a ferromagnetic metal and S is a singlet superconductor), where the long-range triplet superconducting component is generated at noncollinear magnetizations of the F layers. In this paper we demonstrate a possibility of the spin-valve effect mode selection (standard switching effect, the triplet spin-valve effect or reentrant T{sub c}(α) dependence) by the variation of the F2/F1 interface transparency. - Highlights: • T{sub c} of FFS trilayer as a function of angle between magnetizations is calculated. • T{sub c} of FFS structure for arbitrary FF interface transparencies γ{sub B} is calculated. • Possibility of the spin-valve effect mode selection by the variation of γ{sub B} is shown.

  16. Recent emergence of photon upconversion based on triplet energy migration in molecular assemblies. (United States)

    Yanai, Nobuhiro; Kimizuka, Nobuo


    An emerging field of triplet energy migration-based photon upconversion (TEM-UC) is reviewed. Highly efficient photon upconversion has been realized in a wide range of chromophore assemblies, such as non-solvent liquids, ionic liquids, amorphous solids, gels, supramolecular assemblies, molecular crystals, and metal-organic frameworks (MOFs). The control over their assembly structures allows for unexpected air-stability and maximum upconversion quantum yield at weak solar irradiance that has never been achieved by the conventional molecular diffusion-based mechanism. The introduction of the "self-assembly" concept offers a new perspective in photon upconversion research and triplet exciton science, which show promise for numerous applications ranging from solar energy conversion to chemical biology.

  17. Cortical subarachnoid hemorrhage associated with reversible cerebral vasoconstriction syndrome after elective triplet cesarean delivery. (United States)

    Albano, Beatrice; Del Sette, Massimo; Roccatagliata, Luca; Gandolfo, Carlo; Primavera, Alberto


    Reversible cerebral vasoconstriction syndromes (RCVS) comprise a group of disorders characterized by prolonged, but reversible vasoconstriction of the cerebral arteries, usually associated with acute-onset, severe, recurrent headaches, with or without additional neurological signs and symptoms. Various complications of this condition have been observed, such as cortical subarachnoid hemorrhages (cSAH), intracerebral hemorrhages, reversible posterior leukoencephalopathy, ischaemic strokes and transient ischaemic attacks. It is important to include RCVS in thunderclap headache differential diagnosis and among non-aneurismatic subarachnoid hemorrhage causes. In the past years, thanks to the major diffusion of new diagnostic tools such as magnetic resonance, computed tomography and digital subtraction angiography, RCVS have been demonstrated to be more frequent than previously thought. We report an illustrative case of a woman affected by a small cSAH, associated to RCVS, after elective triplet cesarean delivery. To our knowledge, this is the first case of cSAH associated to RCVS after a triplet pregnancy.

  18. Tailor-made RNAi knockdown against triplet repeat disease-causing alleles. (United States)

    Takahashi, Masaki; Watanabe, Shoko; Murata, Miho; Furuya, Hirokazu; Kanazawa, Ichiro; Wada, Keiji; Hohjoh, Hirohiko


    Nucleotide variations, including SNPs, in the coding regions of disease genes are important targets for RNAi treatment, which is a promising medical treatment for intractable diseases such as triplet repeat diseases. However, the identification of such nucleotide variations and the design of siRNAs conferring disease allele-specific RNAi are quite difficult. In this study we developed a pull-down method to rapidly identify coding SNP (cSNP) haplotypes of triple repeat, disease-causing alleles, and we demonstrated disease allele-specific RNAi that targeted cSNP sites in mutant Huntingtin alleles, each of which possessed a different cSNP haplotype. Therefore, the methods presented here allow for allele-specific RNAi knockdown against disease-causing alleles by using siRNAs specific to disease-linked cSNP haplotypes, and advanced progress toward tailor-made RNAi treatments for triplet repeat diseases.

  19. Contribution of satellite lines to temperature diagnostics with He-like triplet lines in photoionized plasma (United States)

    Wang, Feilu; Han, Bo; Salzmann, David; Zhao, Gang


    In the present paper, the He α triplet line ratios (resonance, intercombination, and forbidden lines) are computed for photoionized plasmas, when the contributions of nearby satellite lines are taken into account. The computations have been carried out with our radiative-collisional code, RCF, which is based on the flexible atomic code. The calculations of these line ratios have been done for three materials, namely, silicon, magnesium, and neon. Our calculations are used to derive the plasma temperatures for several astronomical objects, where the spectra are emitted from photoionizing plasmas. It is shown that the incorporation of the satellite lines from doubly excited Li-like ions into the He α triplet lines is necessary to obtain reliable temperature diagnostics for these astrophysical objects.

  20. Neutrino dark energy and leptogenesis with TeV scale triplets

    Energy Technology Data Exchange (ETDEWEB)

    Hati, Chandan [Physical Research Laboratory, Ahmedabad (India); Indian Institute of Technology Gandhinagar, Chandkheda, Ahmedabad (India); Sarkar, Utpal [Physical Research Laboratory, Ahmedabad (India)


    We propose a realization of mass varying neutrino dark energy in two extensions of the Standard Model (SM) with a dynamical neutrino mass related to the acceleron field while satisfying the naturalness. In the first scenario the SM is extended to include a TeV scale scalar Higgs triplet (ξ) and a TeV scale second Higgs doublet (η), while in the second scenario an extension of the SM with fermion triplet (Σ) is considered. We also point out the possible leptogenesis mechanisms for simultaneously generating the observed baryon asymmetry of the universe in both scenarios and discuss the collider signatures for the TeV scale new fields which make these models testable in the current run of LHC. (orig.)

  1. Experimental investigation of the role of the triplet pairing in the superconducting spin-valve effect (United States)

    Leksin, P. V.; Kamashev, A. A.; Garif'yanov, N. N.; Validov, A. A.; Fominov, Ya. V.; Schumann, J.; Kataev, V. E.; Büchner, B.; Garifullin, I. A.


    An important role of the morphology of a superconducting layer in the superconducting spin-valve effect has been established. The triplet pairing induced by the superconductor/ferromagnet proximity effect has been experimentally investigated for samples CoO x /Py1/Cu/Py2/Cu/Pb (where Py = Ni0.81Fe0.19) with a smooth superconducting layer. The optimization of the parameters of this structure has demonstrated a complete switching between the normal and superconducting states with a change in the relative orientation of magnetizations of the ferromagnetic layers from the antiparallel to orthogonal orientation. A pure triplet contribution has been observed for the sample with a permalloy layer thickness at which the superconducting spin-valve effect vanishes. A direct comparison of the experimental data with the theoretical calculation of the temperature of the transition to the superconducting state has been performed for the first time.

  2. Magnetoelectric Andreev Effect due to Proximity-Induced Nonunitary Triplet Superconductivity in Helical Metals (United States)

    Tkachov, G.


    Noncentrosymmetric superconductors exhibit the magnetoelectric effect, which manifests itself in the appearance of the magnetic spin polarization in response to a dissipationless electric current (supercurrent). While much attention has been dedicated to the thermodynamic version of this phenomenon (Edelstein effect), nonequilibrium transport magnetoelectric effects have not been explored yet. We propose the magnetoelectric Andreev effect (MAE), which consists in the generation of spin-polarized triplet Andreev conductance by an electric supercurrent. The MAE stems from the spin polarization of the Cooper-pair condensate due to a supercurrent-induced nonunitary triplet pairing. We propose the realization of such a nonunitary pairing and MAE in superconducting proximity structures based on two-dimensional helical metals—strongly spin-orbit-coupled electronic systems with the Dirac spectrum such as the topological surface states. Our results uncover an unexplored route towards electrically controlled superconducting spintronics and are a smoking gun for induced unconventional superconductivity in spin-orbit-coupled materials.

  3. Using less Quantum Resource for Probabilistic Controlled Teleportation of a Triplet W State

    Directory of Open Access Journals (Sweden)

    Xian-Ming Wang


    Full Text Available In a recent paper [CHIN. PHYS. LETT. Vol.26,No.7(2009070306 ], DONG et al. proposed a scheme for probabilistic controlled teleportation of a triplet W state using combined non-maximally entangled channel of two Einstein–Podolsky–Rosen (EPR states and one Greenberger–Horne–Zeilinger (GHZ state. In this paper ,only using one Einstein–Podolsky–Rosen (EPR state and one Greenberger–Horne–Zeilinger (GHZ state,the scheme for probabilistic controlled teleportation of a triplet W state is presented. Furthermore, Comparing with the widely used Bell-State measurement, Alice performs orthogonal complete basis measurement in the current work. Then Bob can faithfully reconstruct the original state by performing relevant unitary transformations. The total probability of successful teleportation is only dependent on channel coefficients of EPR state and GHZ state.  

  4. Singlet-Triplet Transitions of a P(o)schl-Teller Quantum Dot

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-Fang


    We study the energy spectra of a two-dimensional two-electron quantum dot (QD) with P(o)schl-Teller confining potential under the influence of perpendicular homogeneous magnetic field. Calculations are made by using the method of numerical diagonalization of Hamiltonian matrix within the effective-mass approximation. A ground-state behavior (spin singlet-triplet transitions) as a function of the strength of a magnetic field is found. We find that the dot radius R of a P(o)schl-Teller potential is important for the ground-state transition and the feature of ground-state for a P(o)schl-Teller QD and a parabolic QD is similar when R is larger. The larger the well depth, the higher the magnetic field for the singlet-triplet transition of the ground-state of two interacting electrons in a P(o)schl-Teller QD.

  5. Identification of redundant and synergetic circuits in triplets of electrophysiological data (United States)

    Erramuzpe, Asier; Ortega, Guillermo J.; Pastor, Jesus; de Sola, Rafael G.; Marinazzo, Daniele; Stramaglia, Sebastiano; Cortes, Jesus M.


    Objective. Neural systems are comprised of interacting units, and relevant information regarding their function or malfunction can be inferred by analyzing the statistical dependencies between the activity of each unit. While correlations and mutual information are commonly used to characterize these dependencies, our objective here is to extend interactions to triplets of variables to better detect and characterize dynamic information transfer. Approach. Our approach relies on the measure of interaction information (II). The sign of II provides information as to the extent to which the interaction of variables in triplets is redundant (R) or synergetic (S). Three variables are said to be redundant when a third variable, say Z, added to a pair of variables (X, Y), diminishes the information shared between X and Y. Similarly, the interaction in the triplet is said to be synergetic when conditioning on Z enhances the information shared between X and Y with respect to the unconditioned state. Here, based on this approach, we calculated the R and S status for triplets of electrophysiological data recorded from drug-resistant patients with mesial temporal lobe epilepsy in order to study the spatial organization and dynamics of R and S close to the epileptogenic zone (the area responsible for seizure propagation). Main results. In terms of spatial organization, our results show that R matched the epileptogenic zone while S was distributed more in the surrounding area. In relation to dynamics, R made the largest contribution to high frequency bands (14-100 Hz), while S was expressed more strongly at lower frequencies (1-7 Hz). Thus, applying II to such clinical data reveals new aspects of epileptogenic structure in terms of the nature (redundancy versus synergy) and dynamics (fast versus slow rhythms) of the interactions. Significance. We expect this methodology, robust and simple, can reveal new aspects beyond pair-interactions in networks of interacting units in other

  6. Beginning Chemistry Teachers Use of the Triplet Relationship During their First Three Years in the Classroom (United States)

    Adams, Krista

    Pedagogical content knowledge (PCK) has been described as the knowledge teachers' use in the process of designing and implementing lessons to a particular group of students. This includes the most effective representations that make the content understandable to students, together with the preconceptions and misconceptions that students hold. For chemistry, students have been found to have difficulty with the discipline due to its reliance upon three levels of representation called the triplet: the macro, the submicro, and the symbolic. This study examines eight beginning chemistry teachers' depiction of the chemistry content through the triplet relationship and modifications as a result of considering students' understanding across the teacher's first three years in the classroom. The data collected included classroom observations, interviews, and artifacts for the purpose of triangulation. The analysis of the data revealed that beginning chemistry teachers utilized the abstract components, submicro and symbolic, primarily in the first year. However, the teachers began to engage more macro representations over time building a more developed instructional repertoire. Additionally, teachers' developed an awareness of and responded to their students' understanding of learning atomic structure during the second and third year teaching. The results of this study call for preservice and induction programs to help novice chemistry teachers build a beginning repertoire that focuses on the triplet relationship. In so doing, the teachers enter the classroom with a repertoire that allows them to address the needs of their students. Finally, the study suggests that the triplet relationship framework should be revisited to include an additional component that frames learning to account for socioscientific issues and historical contributions.

  7. Efficient Algorithms for Computing the Triplet and Quartet Distance Between Trees of Arbitrary Degree

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf; Mailund, Thomas;


    ), respectively, and counting how often the induced topologies in the two input trees are different. In this paper we present efficient algorithms for computing these distances. We show how to compute the triplet distance in time O(n log n) and the quartet distance in time O(d n log n), where d is the maximal......, our algorithms improve on all these algorithms...

  8. Photoinduced charge injection from excited triplet hypocrellin B into TiO2 colloid in ethanol

    Institute of Scientific and Technical Information of China (English)

    SHEN, Jian-Quan; SHEN, Tao; ZHANG, Man-Hua; LI, Wen; SONG, Ai-Min


    Photosensitization of TiO2 colloid by hypocrellin B (HB), a natural photodynamic pigment with extremely high plhotosta bility, has been studied by surface enhanced Raman spec troscorpy (SERS), laser flash photolysis and electron param agnetic resonance (EPR) techniques. The photosensitization of TiO2 occurred practically from the excited triplet dye and the electron injection rate constant is 1.3 × 106 s-1. The influ ences of donor and acceptor on the eleciron injection were in vestigated.

  9. Quantum Computing via Singlet-Triplet Spin Qubits in Nanowire Double Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    XUE Peng


    We propose a new structure for quantum computing via spin qubits with high fidelity.Each spin qubit corresponds to two electrons in a nanowire double quantum dot,with the singlet and one of the triplets as the logical qubit states.The entangling gate is effected by virtual charge dipole transitions.We include noise to show the feasibility of this scheme under current experimental conditions.

  10. Implications of the discovery of a Higgs triplet on electroweak right-handed neutrinos

    CERN Document Server

    Aranda, Alfredo; Hung, P Q


    Electroweak scale active right-handed neutrinos such as those proposed in a recent model necessitate the enlargement of the SM Higgs sector to include Higgs triplets with doubly charged scalars. The search for and constraints on such Higgs sector has implications not only on the nature of the electroweak symmetry breaking but also on the possibility of testing the seesaw mechanism at colliders such as the LHC and the ILC.

  11. Fusion Rules of the ${\\cal W}_{p,q}$ Triplet Models

    CERN Document Server

    Wood, Simon


    In this paper we determine the fusion rules of the logarithmic ${\\calW}_{p,q}$ triplet theory and construct the Grothendieck group with subgroups for which consistent product structures can be defined. The fusion rules are then used to determine projective covers. This allows us also to write down a candidate for a modular invariant partition function. Our results demonstrate that recent work on the ${\\cal W}_{2,3}$ model generalises naturally to arbitrary (p,q).

  12. The low lying modes of triplet-condensed neutron matter and their effective theory

    CERN Document Server

    Bedaque, Paulo F


    The condensation of neutrons into a 3P2 superfluid phase occurs at densities relevant for the interior of neutron stars. The triplet pairing breaks rotational symmetry spontaneously and leads to the existence of gapless modes (angulons) that are relevant for many transport coefficients and to the star's cooling properties. We derive the leading terms of the low energy effective field theory, including the leading coupling to electroweak currents, valid for a variety of possible 3P2 phases.

  13. Singlet-triplet fission of carotenoid excitation in light-harvesting LH2 complexes of purple phototrophic bacteria. (United States)

    Klenina, I B; Makhneva, Z K; Moskalenko, A A; Gudkov, N D; Bolshakov, M A; Pavlova, E A; Proskuryakov, I I


    The current generally accepted structure of light-harvesting LH2 complexes from purple phototrophic bacteria conflicts with the observation of singlet-triplet carotenoid excitation fission in these complexes. In LH2 complexes from the purple bacterium Allochromatium minutissimum, a drop in the efficiency of carotenoid triplet generation is demonstrated, which correlates with the extent of selective photooxidation of bacteriochlorophylls absorbing at ~850 nm. We conclude that singlet-triplet fission of carotenoid excitation proceeds with participation of these excitonically coupled bacteriochlorophylls. In the framework of the proposed mechanism, the contradiction between LH2 structure and photophysical properties of carotenoids is eliminated. The possibility of singlet-triplet excitation fission involving a third mediator molecule was not considered earlier.

  14. Vibrational states of the triplet electronic state of H3+. The role of non-adiabatic coupling and geometrical phase

    CERN Document Server

    Alijah, Alexander


    Vibrational energies and wave functions of the triplet state of the H3+ ion have been determined. In the calculations, the ground and first excited triplet electronic states are included as well as the non-Born-Oppenheimer coupling between them. A diabatization procedure transforming the two adiabatic ab initio potential energy surfaces of the triplet-H3+ state into a 2x2 matrix is employed. The diabatization takes into account the non-Born-Oppenheimer coupling and the effect of the geometrical phase due to the conical intersection between the two adiabatic potential surfaces. The results are compared to the calculation involving only the lowest adiabatic potential energy surface of the triplet-H3+ ion and neglecting the geometrical phase. The energy difference between results with and without the non-adiabatic coupling and the geometrical phase is about a wave number for the lowest vibrational levels.

  15. Experimental evidences of singlet to triplet transition in a spin cluster compound

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Tanmoy [Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur Campus, PO: BCKV Campus Main Office, Nadia, Mohanpur 741246, West Bengal (India); Experimental Physics III, Fakultät Physik, TU Dortmund, 44221 Dortmund (Germany); Singh, Harkirat [Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur Campus, PO: BCKV Campus Main Office, Nadia, Mohanpur 741246, West Bengal (India); Department of Condensed Matter Physics and Material Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India); Mitra, Chiranjib, E-mail: [Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur Campus, PO: BCKV Campus Main Office, Nadia, Mohanpur 741246, West Bengal (India)


    Experimental realization of magnetic field induced singlet to triplet transition is reported for NH{sub 4}CuPO{sub 4}·H{sub 2}O, a two spin cluster material with isotropic Heisenberg interaction. Experimental magnetization and specific heat data have been collected as a function of temperature and magnetic field. Experimental data have been analyzed in terms of Heisenberg dimer model. Two quantum complementary observables representing local and non-local properties of the spins are constructed using the experimental data and a clear evidence of singlet to triplet transition is observed through partial quantum information sharing when the magnetic field is swept through a particular value. Signature of this transition has also been captured when specific heat is measured as a function of magnetic field. Furthermore, using the experimental specific heat data, magnetic energy values are calculated and their variations are captured as a function of magnetic field and temperature. - Highlights: • Magnetic field induced energy level crossing is reported for NH{sub 4}CuPO{sub 4}·H{sub 2}O. • Magnetic data are analyzed within the framework of spin 1/2 dimer model. • Singlet-triplet transition is captured employing quantum complementarity principle. • Field dependent specific heat data also provides the signature of the transition.

  16. Genome-Wide Demethylation Promotes Triplet Repeat Instability Independently of Homologous Recombination (United States)

    Dion, Vincent; Lin, Yunfu; Price, Brandee A.; Fyffe, Sharyl L.; Seluanov, Andrei; Gorbunova, Vera; Wilson, John H.


    Trinucleotide repeat instability is intrinsic to a family of human neurodegenerative diseases. The mechanism leading to repeat length variation is unclear. We previously showed that treatment with the demethylating agent 5-aza-2′-deoxycytidine (5-aza-CdR) dramatically increases triplet repeat instability in mammalian cells. Based on previous reports that demethylation increases homologous recombination (HR), and our own observations that HR destabilizes triplet repeats, we hypothesized that demethylation alters repeat stability by stimulating HR. Here, we test that hypothesis at the Aprt (adenosine phosphoribosyl transferase) locus in CHO cells, where CpG demethylation and HR have both been shown to increase CAG repeat instability. We find that the rate of HR at the Aprt locus is not altered by demethylation. The spectrum of recombinants, however, was shifted from the usual 6:1 ratio of conversions to crossovers to more equal proportions in 5-aza-CdR-treated cells. The subtle influences of demethylation on HR at the Aprt locus are not sufficient to account for its dramatic effects on repeat instability. We conclude that 5-aza-CdR promotes triplet repeat instability independently of HR. PMID:18083071

  17. Helical Self-Assembly-Induced Singlet-Triplet Emissive Switching in a Mechanically Sensitive System. (United States)

    Wu, Hongwei; Zhou, Yunyun; Yin, Liyuan; Hang, Cheng; Li, Xin; Ågren, Hans; Yi, Tao; Zhang, Qing; Zhu, Liangliang


    In nanoscience, chirality has shown a significant ability to tune materials' electronic properties, whereas imposing macrochirality into the regulation of singlet-triplet features of organic optoelectronics remains a challenging research topic. Since the tuning for singlet and triplet excited-state properties in a single π-functional molecule connects to its multicolor luminescent application and potential improvement of internal quantum efficiency, we here report that supramolecular chirality can be employed to toggle the singlet and triplet emissions in a well-designed asterisk-shaped molecule. Employing a hexathiobenzene-based single luminophore as a prototype and functionalizing it with chiral α-lipoiate side groups, we find that helical nanoarchitectures can accordingly form in mixed DMF/H2O solution. On this basis, switching between fluorescence and phosphorescence of the material can be realized upon helical self-assembly and dissociation. Such a behavior can be attributed to a helical-conformation-dependent manipulation of the intersystem crossing. Furthermore, reversible mechanoluminescence of the corresponding solid sample was also observed to rely on an analogous molecular self-assembly alternation. These results can probably provide new visions for the development of next-generation supramolecular chiral functional materials.

  18. Quantum dynamics study of singlet-triplet transitions in s-trans-1,3-butadiene (United States)

    Nikoobakht, Behnam; Köppel, Horst


    The intersystem crossing dynamics of s-trans-1,3-butadiene in its lowest singlet and triplet states is studied theoretically, employing a fully quantal approach for the first time. The electronic states 21Ag, 11Bu, 13Bu and 13Ag, which interact vibronically and via the spin-orbit coupling are treated in the calculation, thus covering the lowest spin-forbidden electronic transitions. Up to five nuclear degrees of freedom, including out-of-plane dihedral angles are included in our investigation. The calculation of potential energy surfaces relies on the CASPT2 method, and the evaluation of spin-orbit coupling matrix elements using the full two-electron Breit-Pauli Hamiltonian is performed by utilizing the MRCI wavefunction. The latter dependence on the nuclear coordinates is included for the first time. An electronic population transfer on the sub-picosecond time scale due to intersystem crossing is obtained, a mechanism that can contribute to the singlet-triplet transitions in the electron energy loss spectrum of s-trans-1, 3-butadiene. It is found that the dependence of the spin-orbit coupling on the out-of-plane coordinates plays a dominant role in these singlet-triplet transitions. The amount of population transfer to the 13Ag and 13Bu states is roughly of the same order of magnitude.

  19. The protein's role in triplet energy transfer in bacterial reaction centers.

    Energy Technology Data Exchange (ETDEWEB)

    Laible, P. D.


    When photosynthetic organisms are subjected to high-light conditions in nature, electron transfer becomes blocked as the rate of conversion of light into charge-separated states in the reaction center (RC) exceeds the capacity of the soluble carriers involved in cyclic electron transfer. In that event, a well-characterized T{sub 0}-polarized triplet state {sup T}P, is formed on the primary donor, P, from the P{sup +}H{sub A}{sup {minus}} state (reviewed in [1]). In an aerobic or semi-aerobic environment, the major role of the carotenoid (C), also bound by the RC, is to quench {sup T}P prior to its sensitization of the {sup 1}{Delta}{sub g} singlet state of oxygen--a potentially damaging biological oxidant. The carotenoid performs this function efficiently in most bacterial RCs by rapidly accepting the triplet state from P and dissipating this excited-state energy into heat through internal conversion. The lowest-lying triplet states of P and the carotenoid are sufficiently different that {sup T}P can promote oxygen to its excited singlet state whereas {sup T}C can quench the {sup T}P state (reviewed in [2]).

  20. Triplet state dissolved organic matter in aquatic photochemistry: reaction mechanisms, substrate scope, and photophysical properties. (United States)

    McNeill, Kristopher; Canonica, Silvio


    Excited triplet states of chromophoric dissolved organic matter ((3)CDOM*) play a major role among the reactive intermediates produced upon absorption of sunlight by surface waters. After more than two decades of research on the aquatic photochemistry of (3)CDOM*, the need for improving the knowledge about the photophysical and photochemical properties of these elusive reactive species remains considerable. This critical review examines the efforts to date to characterize (3)CDOM*. Information on (3)CDOM* relies mainly on the use of probe compounds because of the difficulties associated with directly observing (3)CDOM* using transient spectroscopic methods. Singlet molecular oxygen ((1)O2), which is a product of the reaction between (3)CDOM* and dissolved oxygen, is probably the simplest indicator that can be used to estimate steady-state concentrations of (3)CDOM*. There are two major modes of reaction of (3)CDOM* with substrates, namely triplet energy transfer or oxidation (via electron transfer, proton-coupled electron transfer or related mechanisms). Organic molecules, including several environmental contaminants, that are susceptible to degradation by these two different reaction modes are reviewed. It is proposed that through the use of appropriate sets of probe compounds and model photosensitizers an improved estimation of the distribution of triplet energies and one-electron reduction potentials of (3)CDOM* can be achieved.

  1. Analysis of Triplet Exciton Loss Pathways in PTB7:PC71BM Bulk Heterojunction Solar Cells (United States)

    Kraus, Hannes; Heiber, Michael C.; Väth, Stefan; Kern, Julia; Deibel, Carsten; Sperlich, Andreas; Dyakonov, Vladimir


    A strategy for increasing the conversion efficiency of organic photovoltaics has been to increase the VOC by tuning the energy levels of donor and acceptor components. However, this opens up a new loss pathway from an interfacial charge transfer state to a triplet exciton (TE) state called electron back transfer (EBT), which is detrimental to device performance. To test this hypothesis, we study triplet formation in the high performing PTB7:PC71BM blend system and determine the impact of the morphology-optimizing additive 1,8-diiodoctane (DIO). Using photoluminescence and spin-sensitive optically detected magnetic resonance (ODMR) measurements at low temperature, we find that TEs form on PC71BM via intersystem crossing from singlet excitons and on PTB7 via EBT mechanism. For DIO blends with smaller fullerene domains, an increased density of PTB7 TEs is observed. The EBT process is found to be significant only at very low temperature. At 300 K, no triplets are detected via ODMR, and electrically detected magnetic resonance on optimized solar cells indicates that TEs are only present on the fullerenes. We conclude that in PTB7:PC71BM devices, TE formation via EBT is impacted by fullerene domain size at low temperature, but at room temperature, EBT does not represent a dominant loss pathway.

  2. Magnetic dipolar interaction between correlated triplets created by singlet fission in tetracene crystals

    CERN Document Server

    Wang, Rui; Zhang, Bo; Liu, Yunlong; Wang, Xiaoyong; Xiao, Min


    Singlet fission (SF) can potentially break the Shockley-Queisser efficiency limit in single-junction solar cells by splitting one photo-excited singlet exciton (S1) into two triplets (2T1) in organic semiconductors. A dark multi-exciton (ME) state has been proposed as the intermediate connecting S1 to 2T1. However, the exact nature of this ME state, especially how the doubly-excited triplets interact, remains elusive. Here, we report a quantitative study on the magnetic dipolar interaction between SF-induced correlated triplets in tetracene crystals by monitoring quantum beats relevant to the ME sublevels at room temperature. The resonances of ME sublevels approached by tuning an external magnetic field are observed to be avoided, which agrees well with the theoretical predictions considering a magnetic dipolar interaction of ~ 0.008 GHz. Our work paves a way to quantify the magnetic dipolar interaction in organic materials and marks an important step towards understanding the underlying physics of the ME sta...

  3. Time-resolved spectroscopic studies of sulphonated aluminium phthalocyanine triplet states (United States)

    Simpson, Mary S. C.; Beeby, A.; Bishop, Steven M.; MacRobert, Alexander J.; Parker, Andrew W.; Phillips, David


    The photophysical and photochemical properties of sulphonated aluminum and zinc phthalocyanines have been investigated in a range of solvents and model biological systems. Anomalous effects are observed upon deuteration of the solvent and addition of fluoride ions. In D2O the excited singlet and triplet state lifetimes and quantum yields of fluorescence and triplet state formation are increased relative to H2O. No solvent isotope effect is observed between CH3OH and CH3OD. It is proposed that relaxation of the excited state involves a tunnelling type interaction in which the phthalocyanine's highly energetic metal-axial ligand stretching vibrations are coupled to the HO-H or DO-D stretching vibrations. A significant increase in triplet lifetimes of phthalocyanine sensitizers bound to protein substrates is observed which is a function of the degree of sulphonation. The implications of these results to the determination of the quantum yields of singlet oxygen formation in D2O and lipophilic environments are discussed.

  4. Dichorionic triamniotic triplet pregnancy complicated by twin anemia polycythemia sequence: the place of fetal therapy. (United States)

    Griersmith, Thérèse H; Fung, Alison M; Walker, Susan P


    Monochorionic twins as part of a high order multiple pregnancy can be an unintended consequence of the increasingly common practice of blastocyst transfer for couples requiring in vitro fertilisation (IVF) for infertility. Dichorionic triamniotic (DCTA) triplets is the most common presentation, and these pregnancies are particularly high risk because of the additional risks associated with monochorionicity. Surveillance for twin-to-twin transfusion syndrome, including twin anemia polycythemia sequence, may be more difficult, and any intervention to treat the monochorionic pair needs to balance the proposed benefits against the risks posed to the unaffected singleton. Counseling of families with DCTA triplets is therefore complex. Here, we report a case of DCTA triplets, where the pregnancy was complicated by threatened preterm labour, and twin anemia polycythemia sequence (TAPS) was later diagnosed at 28 weeks. The TAPS was managed with a single intraperitoneal transfusion, enabling safe prolongation of the pregnancy for over 2 weeks until recurrence of TAPS and preterm labour supervened. Postnatal TAPS was confirmed, and all three infants were later discharged home at term corrected age, and were normal at follow-up. This case highlights that in utero therapy has an important role in multiple pregnancies of mixed chorionicity, and can achieve safe prolongation of pregnancy at critical gestations.

  5. Non-Linear Advanced Control of the LHC Inner Triplet Heat Exchanger Test Unit

    CERN Document Server

    Blanco-Viñuela, E; De Prada-Moraga, C; Cristea, S


    The future Large Hadron Collider (LHC) at CERN will include eight interaction region final focus magnet systems, the so-called "Inner Triplet", one on each side of the four beam collision points. The Inner Triplets will be cooled in a static bath of pressurized He II nominally at 1.9 K. This temperature is a control parameter and has very severe constraints in order to avoid the transition from the superconducting to normal resistive state. The main difference in these special zones with respect to a regular LHC cell is higher dynamic heat load unevenly distributed which modifies largely the process characteristics and hence the controller performance. Several control strategies have already been tested at CERN in a pilot plant (LHC String Test) which reproduced a LHC half-cell. In order to validate a common control structure along the whole LHC ring, a Nonlinear Model Predictive Control (NMPC) has been developed and implemented in the Inner Triplet Heat Exchanger Unit (IT-HXTU) at CERN. Automation of the Inn...

  6. Fluorescence via Reverse Intersystem Crossing from Higher Triplet States in a Bisanthracene Derivative

    CERN Document Server

    Sato, Tohru; Haruta, Naoki; Pu, Yong-Jin


    To elucidate the high external quantum efficiency observed for organic light-emitting diodes using a bisanthracene derivative, BD1, as the emitting molecule, off-diagonal vibronic coupling constants (VCCs) between the excited states of BD1, which govern non-radiative transition rates, were calculated employing time-dependent density functional theory. The VCCs were analysed based on the concept of vibronic coupling density. The VCC calculations suggest a fluorescence via higher triplets (FvHT) mechanism, which entails the conversion of a T$_4$ exciton generated during electrical excitation into an S$_2$ exciton via reverse intersystem crossing (RISC); moreover, the S$_2$ exciton relaxes to a fluorescent S$_1$ exciton because of large vibronic coupling between S$_2$ and S$_1$. This mechanism is valid as long as the relaxation of triplet states higher than T$_1$ to lower states is suppressed. The symmetry-controlled thermally activated delayed fluorescence (SC-TADF) and inverted singlet and triplet (iST) struct...

  7. Charge transfer and triplet states in OPV materials and devices (Presentation Recording) (United States)

    Dyakonov, Vladimir


    Electron back transfer (EBT), potentially occurring after electron transfer from donor to acceptor may populate the lower lying donor or acceptor triplet state and serve as recombination channel.[1] Here we report on studies of charge transfer and triplet states in blends of highly efficient benzodithiophene PTB7 polymer in combination with the fullerene-derivative PC71BM using the spin sensitive optically detected magnetic resonance (ODMR) technique and compare the results with those obtained in P3HT (poly(3- hexylthiophene):PC61BM blends. Although PTB7:PC71BM absorbers yield much higher power conversion efficiencies in solar cells exceeding 7%, we found a significant increase of triplet exciton generation, which was absent in the P3HT based blends. We discuss this observation within the EBT scenario with the emphasis on the influence of morphology, fullerene load, HOMO/LUMO energy and presence of additives (DIO). Suppressing the EBT process by morphology and/or energetics of polymer and molecules is important to achieve the full potential of highly efficient OPV materials. [1] M. Liedtke, et al., JACS 133, 9088 (2011).

  8. Phenomenology of a Higgs triplet model at future $e^{+}e^{-}$ colliders

    CERN Document Server

    Blunier, Sylvain; Díaz, Marco Aurelio; Koch, Benjamin


    In this work, we investigate the prospects of future $e^{+}e^{-}$ colliders in testing a Higgs triplet model with a scalar triplet and a scalar singlet under $SU(2)$. The parameters of the model are fixed so that the lightest $CP-$even state corresponds to the Higgs particle observed at the LHC at around $125$ GeV. This study investigates if the second heaviest $CP-$even, the heaviest $CP-$odd and the singly charged states can be observed at existing and future colliders by computing their accessible production and decay channels. In particular, the LHC is not well equipped to produce a Higgs boson which is not mainly doublet-like, so we turn our focus to lepton colliders. We find distinctive features of this model in cases when the second heaviest $CP-$even Higgs is triplet-like, singlet-like or a mixture. These features could distinguish the model from other scenarios at future $e^{+}e^{-}$ colliders.

  9. HLA class I donor-specific triplet antibodies detected after renal transplantation. (United States)

    Varnavidou-Nicolaidou, A; Doxiadis, I I N; Iniotaki-Theodoraki, A; Patargias, T; Stavropoulos-Giokas, C; Kyriakides, G K


    The purpose of this study was to investigate whether IgG, non-donor-specific anti-HLA class I antibodies (HLAabI) detected after renal transplantation recognize immunogenic amino acid triplets expressed on the foreign graft. In addition, we sought to evaluate the effect of these antibodies as well as other posttransplant HLAabI on graft outcome. Posttransplant sera from 264 renal recipients were tested for the presence of IgG HLAabI and HLA class II-specific alloantibodies (HLAabII) by ELISA. The HLAMatchmaker computer algorithm was used to define the HLA class I non-donor-specific antibodies, which seem to recognize immunogenic amino acid triplets. Donor-specific triplet antibodies (DSTRab) were detected in 16 of 22 (72.7%) recipients based on at least one HLA-A or -B mismatched antigen with the donor. DSTRab were found either without (n = 7) or with (n = 9) HLA donor-specific antibodies (HLA-DSA). The presence of DSTRab alone in the periphery was associated with acute rejection, whereas the presence of both DSTRab and HLA-DSA was associated with chronic rejection and graft failure.

  10. Lamb shift in radical-ion pairs produces a singlet-triplet energy splitting in photosynthetic reaction centers


    Vitalis, K. M.; Kominis, I. K.


    Radical-ion pairs, fundamental for understanding photosynthesis and the avian magnetic compass, were recently shown to be biological open quantum systems. We here show that the coupling of the radical-pair's spin degrees of freedom to its decohering vibrational reservoir leads to a shift of the radical-pair's magnetic energy levels. The Lamb shift Hamiltonian is diagonal in the singlet-triplet basis, and results in a singlet-triplet energy splitting physically indistinguishable from an exchan...

  11. Photo-assisted intersystem crossing: The predominant triplet formation mechanism in some isolated polycyclic aromatic molecules excited with pulsed lasers

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Philip M., E-mail: [Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400 (United States); Sears, Trevor J. [Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400 (United States); Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973 (United States)


    Naphthalene, anthracene, and phenanthrene are shown to have very long-lived triplet lifetimes when the isolated molecules are excited with nanosecond pulsed lasers resonant with the lowest singlet state. For naphthalene, triplet state populations are created only during the laser pulse, excluding the possibility of normal intersystem crossing at the one photon level, and all molecules have triplet lifetimes greater than hundreds of microseconds, similar to the behavior previously reported for phenylacetylene. Although containing 7–12 thousand cm{sup −1} of vibrational energy, the triplet molecules have ionization thresholds appropriate to vibrationless T{sub 1} states. The laser power dependences (slopes of log-log power plots) of the excited singlet and triplet populations are about 0.7 for naphthalene and about 0.5 for anthracene. Kinetic modeling of the power dependences successfully reproduces the experimental results and suggests that the triplet formation mechanism involves an enhanced spin orbit coupling caused by sigma character in states at the 2-photon level. Symmetry adapted cluster-configuration interaction calculations produced excited state absorption spectra to provide guidance for estimating kinetic rates and the sigma character present in higher electronic states. It is concluded that higher excited state populations are significant when larger molecules are excited with pulsed lasers and need to be taken into account whenever discussing the molecular photodynamics.

  12. EPR characterisation of the triplet state in photosystem II reaction centers with singly reduced primary acceptor Q(A). (United States)

    Feikema, W Onno; Gast, Peter; Klenina, Irina B; Proskuryakov, Ivan I


    The triplet states of photosystem II core particles from spinach were studied using time-resolved cw EPR technique at different reduction states of the iron--quinone complex of the reaction center primary electron acceptor. With doubly reduced primary acceptor, the well-known photosystem II triplet state characterised by zero-field splitting parameters |D|=0.0286 cm(-1), |E|=0.0044 cm(-1) was detected. When the primary acceptor was singly reduced either chemically or photochemically, a triplet state of a different spectral shape was observed, bearing the same D and E values and characteristic spin polarization pattern arising from RC radical pair recombination. The latter triplet state was strongly temperature dependent disappearing at T=100 K, and had a much faster decay than the former one. Based on its properties, this triplet state was also ascribed to the photosystem II reaction center. A sequence of electron-transfer events in the reaction centers is proposed that explains the dependence of the triplet state properties on the reduction state of the iron--quinone primary acceptor complex.

  13. Dissecting galaxy triplets in the Sloan Digital Sky Survey Data Release 10: I. Stellar populations and emission line analysis

    CERN Document Server

    Costa-Duarte, M V; Duplancic, F; Sodré, L; Lambas, D G


    We identify isolated galaxy triplets in a volume-limited sample from the Sloan Digital Sky Survey Data Release 10. Our final sample has 80 galaxy systems in the redshift range 0.04$\\le$z$\\le$0.1, brighter than $M_r = -20.5 + 5\\log h_{70}$. Spectral synthesis results and WHAN and BPT diagnostic diagrams were employed to classify the galaxies in these systems as star-forming, active nuclei, or passive/retired. Our results suggest that the brightest galaxies drive the triplet evolution, as evidenced by the strong correlations between properties as mass assembly and mean stellar population age with triplet properties. Galaxies with intermediate luminosity or the faintest one within the triplet seem to play a secondary role. Moreover, the relation between age and stellar mass of galaxies is similar for these galaxies but different for the brightest galaxy in the system. Most of the triplet galaxies are passive or retired, according to the WHAN classification. Low mass triplets present different fractions of WHAN c...

  14. The Complementarity of the Loop to the Stem in DNA Pseudoknots Gives Rise to Local TAT Base-Triplets. (United States)

    Reiling-Steffensmeier, Calliste; Marky, Luis A


    Pseudoknots belong to an RNA structural motif that has significant roles in the biological function of RNA. An example is ribosomal frameshifting; in this mechanism, the formation of a local triplex changes the reading frame that allows for differences in the translation of mRNAs. In this work, we have used a combination of temperature-dependent UV spectroscopy and differential scanning calorimetry (DSC) to determine the unfolding thermodynamics of a set of DNA pseudoknots with the following sequence: d(TCTCTTnAAAAAAAAGAGAT5TTTTTTT), where "Tn" is a thymine loop with n=5 (PsK-5), 7 (PsK-7), 9 (PsK-9), or 11 (PsK-11). All four oligonucleotides form intramolecular pseudoknots, and the increase in the length of this loop yielded more stable pseudoknots due to higher transition temperatures and higher unfolding enthalpies. This indicates formation of one and three TAT/TAT stacks in PsK-9 and PsK-11, respectively. We have flipped one AT for a TA base pair in the core stem of these pseudoknots, preventing in this way the formation of these base-triplet stacks. The DSC curves of these pseudoknots yielded lower unfolding enthalpies, confirming the formation of a local triplex in PsK-9 and PsK-11. Furthermore, we have investigated the reaction of PsK-5 and PsK-9 with their partially complementary strands: directly by isothermal titration calorimetry and indirectly by creating a Hess cycle with the DSC data. Relative to the PsK-5 reaction, PsK-9 reacts with its complementary strand with less favorable free energy and enthalpy contributions; this indicates PsK-9 is more stable and more compact due to the formation of a local triplex.

  15. An optical-near-IR study of a triplet of super star clusters in the starburst core of M82

    Energy Technology Data Exchange (ETDEWEB)

    Westmoquette, M. S. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany); Bastian, N. [Excellence Cluster Universe, Boltzmannstrasse 2, D-85748 Garching bei München (Germany); Smith, L. J. [Space Telescope Science Institute and European Space Agency, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Seth, A. C. [University of Utah, Salt Lake City, UT 84112 (United States); Gallagher III, J. S.; Ryon, J. E. [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling, 475 North Charter Street, Madison, WI 53706 (United States); O' Connell, R. W. [Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903 (United States); Silich, S.; Mayya, Y. D.; González, D. Rosa [Instituto Nacional de Astrofísica, Optica y Electronica, Luis Enrique Erro 1, Tonantzintla, C.P. 72840, Puebla (Mexico); Muñoz-Tuñón, C., E-mail: [Instituto de Astrofísica de Canarias, C/vía Láctea s/n, E-38200 La Laguna, Tenerife (Spain)


    We present HST/STIS optical and Gemini/NIFS near-IR IFU spectroscopy and archival Hubble Space Telescope (HST) imaging of the triplet of super star clusters (A1, A2, and A3) in the core of the M82 starburst. Using model fits to the Space Telescope Imaging Spectrograph (STIS) spectra and the weakness of red supergiant CO absorption features (appearing at ∼6 Myr) in the NIFS H-band spectra, the ages of A2 and A3 are 4.5 ± 1.0 Myr. A1 has strong CO bands, consistent with our previously determined age of 6.4 ± 0.5 Myr. The photometric masses of the three clusters are 4-7 × 10{sup 5} M{sub ☉}, and their sizes are R{sub eff} = 159, 104, 59 mas (∼2.8, 1.8, 1.0 pc) for A1, A2, and A3. The STIS spectra yielded radial velocities of 320 ± 2, 330 ± 6, and 336 ± 5 km s{sup –1} for A1, A2, and A3, placing them at the eastern end of the x{sub 2} orbits of M82's bar. Clusters A2 and A3 are in high-density (800-1000 cm{sup –3}) environments, and like A1, are surrounded by compact H II regions. We suggest the winds from A2 and A3 have stalled, as in A1, due to the high ISM ambient pressure. We propose that the three clusters were formed in situ on the outer x{sub 2} orbits in regions of dense molecular gas subsequently ionized by the rapidly evolving starburst. The similar radial velocities of the three clusters and their small projected separation of ∼25 pc suggest that they may merge in the near future unless this is prevented by velocity shearing.

  16. Prediction of plant promoters based on hexamers and random triplet pair analysis

    Directory of Open Access Journals (Sweden)

    Noman Nasimul


    Full Text Available Abstract Background With an increasing number of plant genome sequences, it has become important to develop a robust computational method for detecting plant promoters. Although a wide variety of programs are currently available, prediction accuracy of these still requires further improvement. The limitations of these methods can be addressed by selecting appropriate features for distinguishing promoters and non-promoters. Methods In this study, we proposed two feature selection approaches based on hexamer sequences: the Frequency Distribution Analyzed Feature Selection Algorithm (FDAFSA and the Random Triplet Pair Feature Selecting Genetic Algorithm (RTPFSGA. In FDAFSA, adjacent triplet-pairs (hexamer sequences were selected based on the difference in the frequency of hexamers between promoters and non-promoters. In RTPFSGA, random triplet-pairs (RTPs were selected by exploiting a genetic algorithm that distinguishes frequencies of non-adjacent triplet pairs between promoters and non-promoters. Then, a support vector machine (SVM, a nonlinear machine-learning algorithm, was used to classify promoters and non-promoters by combining these two feature selection approaches. We referred to this novel algorithm as PromoBot. Results Promoter sequences were collected from the PlantProm database. Non-promoter sequences were collected from plant mRNA, rRNA, and tRNA of PlantGDB and plant miRNA of miRBase. Then, in order to validate the proposed algorithm, we applied a 5-fold cross validation test. Training data sets were used to select features based on FDAFSA and RTPFSGA, and these features were used to train the SVM. We achieved 89% sensitivity and 86% specificity. Conclusions We compared our PromoBot algorithm to five other algorithms. It was found that the sensitivity and specificity of PromoBot performed well (or even better with the algorithms tested. These results show that the two proposed feature selection methods based on hexamer frequencies

  17. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., ultrafast lasers (atto- and femto-second lasers) and parametric oscillators, coherent matter waves, Doppler-free Fourier spectroscopy with optical frequency combs, interference spectroscopy, quantum optics, the interferometric detection of gravitational waves and still more applications in chemical analysis, medical diagnostics, and engineering.

  18. Spectroscopy and photophysics of self-organized zinc porphyrin nanolayers. 3. Fluorescence detected magnetic resonance of triplet states

    NARCIS (Netherlands)

    Schaafsma, T.J.; Dag, I.; Sitters, R.; Glasbeek, M.; Lifshitz, E.


    Fluorescence detected magnetic resonance (FDMR) has been applied to ~25-nm-thick porphyrin films, containing ordered domains of zinc tetra-(p-octylphenyl)-porphyrin (ZnTOPP) spin-coated onto quartz slides. Illuminating the films at 1.4 K with 457.9-nm light from a continuous wave Ar+ laser produces

  19. Josephson effect in multiterminal superconductor-ferromagnet junctions coupled via triplet components (United States)

    Moor, Andreas; Volkov, Anatoly F.; Efetov, Konstantin B.


    On the basis of the Usadel equation we study a multiterminal Josephson junction. This junction is composed by "magnetic" superconductors Sm, which have singlet pairing and are separated from the normal n wire by spin filters so that the Josephson coupling is caused only by fully polarized triplet components. We show that there is no interaction between triplet Cooper pairs with antiparallel total spin orientations. The presence of an additional singlet superconductor S attached to the n wire leads to a finite Josephson current IQ with an unusual current-phase relation. The density of states in the n wire for different orientations of spins of Cooper pairs is calculated. We derive a general formula for the current IQ in a multiterminal Josephson contact and apply this formula for analysis of two four-terminal Josephson junctions of different structures. It is shown in particular that both the "nematic" and the "magnetic" cases can be realized in these junctions. In a two-terminal structure with parallel filter orientations and in a three-terminal structure with antiparallel filter orientations of the "magnetic" superconductors with attached additional singlet superconductor, we find a nonmonotonic temperature dependence of the critical current. Also, in these structures, the critical current shows a Riedel peak like dependence on the exchange field in the "magnetic" superconductors. Although there is no current through the S/n interface due to orthogonality of the singlet and triplet components, the phase of the order parameter in the superconuctor S is shown to affect the Josephson current in a multiterminal structure.

  20. Experimental comparative study of doublet and triplet impinging atomization of gelled fuel based on PIV (United States)

    Yang, Jian-lu; Li, Ning; Weng, Chun-sheng


    Gelled propellant is promising for future aerospace application because of its combination of the advantages of solid propellants and liquid propellants. An effort was made to reveal the atomization properties of gelled fuel by particle image velocimetry (PIV) system. The gelled fuel which was formed by gasoline and Nano-silica was atomized using a like-doublet impingement injector and an axisymmetric like-triplet impingement injector. The orifice diameter and length of the nozzle used in this work were of 0.8mm, 4.8mm, respectively. In the impinging spray process, the impingement angles were set at 90° and 120°, and the injection pressures were of 0.50MPa and 1.00MPa. The distance from the exit of the orifice to the impingement point was fixed at 9.6mm. In this study, high-speed visualization and temporal resolution particle image velocimetry techniques were employed to investigate the impingement atomization characteristics. The experimental investigation demonstrated that a long narrow high speed droplets belt formed around the axis of symmetry in the like-doublet impinging atomization area. However, there was no obvious high-speed belt with impingement angle 2θ = 90° and two high-speed belts appeared with impingement angle 2θ = 120° in the like-doublet impingement spray field. The high droplet velocity zone of the like-doublet impingement atomization symmetrically distributed around the central axis, and that of the like-triplet impingement spray deflected to the left of the central axis - opposite of injector. Although the droplets velocity distribution was asymmetry of like-triplet impingement atomization, the injectors were arranged like axisymmetric conical shape, and the cross section of spray area was similar to a circle rather than a narrow rectangle like the like-doublet impingement atomization.

  1. Optimal values of rovibronic energy levels for triplet electronic states of molecular deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Lavrov, B P; Umrikhin, I S [Faculty of Physics, St Petersburg State University, St Petersburg 198504 (Russian Federation)], E-mail:


    An optimal set of 1050 rovibronic energy levels for 35 triplet electronic states of D{sub 2} has been obtained by means of a statistical analysis of all available wavenumbers of triplet-triplet rovibronic transitions studied in emission, absorption, laser and anticrossing spectroscopic experiments of various authors. We used a new method of analysis (Lavrov and Ryazanov 2005 JETP Lett. 81 371-4), which does not need any a priori assumptions concerning the molecular structure, being based on only two fundamental principles: Rydberg-Ritz and maximum likelihood. The method provides the opportunity to obtain the root-mean-square estimates for uncertainties of the experimental wavenumbers independent from those presented in the original papers. A total of 234 from 3822 published wavenumber values were found to be spurious, while the remaining set of the data may be divided into 20 subsets (samples) of uniformly precise data having close to normal distributions of random errors within the samples. New experimental wavenumber values of 125 questionable lines were obtained in the present work. Optimal values of the rovibronic levels were obtained from the experimental data set consisting of 3713 wavenumber values (3588 old and 125 new). The unknown shift between levels of ortho- and para-deuterium was found by least-squares analysis of the a{sup 3}{sigma}{sup +}{sub g}, v = 0, N = 0 to 18 rovibronic levels with odd and even values of N. All the energy levels were obtained relative to the lowest vibro-rotational level (v = 0, N = 0) of the a{sup 3}{sigma}{sup +}{sub g} electronic state, and presented in tabular form together with the standard deviations of the empirical determination. New energy-level values differ significantly from those available in the literature.

  2. Detection of large expansions in myotonic dystrophy type 1 using triplet primed PCR

    Directory of Open Access Journals (Sweden)

    Susmita eSingh


    Full Text Available Myotonic dystrophy type 1 (DM1 is an autosomal dominant neuromuscular disease caused by expansion of a CTG trinucleotide repeat in the DMPK gene. Methodology for genetic testing of DM1 is currently not optimal, in particular for the early-onset patients in pediatric populations where large expanded (CTGn alleles are usually common. Individuals who are homozygous for a normal allele and individuals who are heterozygous for one normal and one large expanded allele are indistinguishable by conventional PCR, as both generate a single product of the normal allele. Thus, reflex Southern blot has often been needed to distinguish these cases. With the aim to decrease the need for reflex Southern blot tests, a novel, single-tube CTG repeat primed PCR technology was designed to distinguish the true homozygous patients from the individuals whose large alleles are missed by conventional PCR. The method utilizes two gene-specific primers that flank the triplet repeat region and a third primer set complementary to the repeated region to detect the large alleles. Compared to traditional PCR, this novel Triplet-repeat Primed PCR can detect the presence of large expanded alleles with demonstrating a ladder pattern. Using this single-step protocol, 45 specimens were tested. The alleles with sizes ≤ 85 repeats were determined by the gene specific primers. 13 abnormal alleles, which missed by the conventional PCR, were successfully detected by the Triplet-repeat Primed PCR. All the abnormal alleles were confirmed and measured by Southern Blot analysis. In summary, optimized TP-PCR can accurately detect the presence of the large expanded alleles. With the ability to distinguish the true homozygous patients from the false negative homozygous individuals, the application of the optimized TP-PCR can significantly reduce the need of Southern Blot tests.

  3. Fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis


    Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses the foundati......Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...

  4. Elastic Scattering of Ultracold 133Cs and 85Rb Atoms in Triplet State

    Institute of Scientific and Technical Information of China (English)

    SUN Jin-Feng; HU Qiu-Bo; ZHU Zun-Lue; WANG Xiao-Fei; ZHANG Ji-Cai


    Elastic scattering properties of the ultracold interaction for the triplet state of 133Cs and 85Rb atoms are studied using two kinds of potentials by the same phase Φ. One is the interpolation potential, and another is Lennard-Jones potential (L J12,6). The radial Schr(o)dinger equation is also solved using two computational methods, the semiclassical method (WKB), and the Numerov method. Our results are found to be in an excellent agreement with the more recent theoretical values. It shows that the two potentials and methods are applicable for studying ultracold collisions between the mixing alkali atoms.

  5. The slab albedo problem for pure-triplet anisotropic scattering by singular eigenfunction method (United States)

    Türeci, D.; Türeci, R. G.


    One-speed, time independent and homogenous medium neutron transport equation can be solved by using pure-triplet anisotropic scattering. This solution bases on finding the Case's eigenfunctions and the orthogonality relations of these eigenfunctions. The infinite medium Green function can be written by using the jump condition after finding Case's eigenfunctions. The slab albedo problem can be investigated as numerical by using suggested solutions over surfaces with the singular eigenfunction method which bases on the infinite medium Green function. The selected numerical results can be tabulated.

  6. Cold Test Results of the Inner Triplet Orbit Correctors for the LHC

    CERN Document Server

    Venturini-Delsolaro, W


    The inner triplet orbit correctors for the LHC, MCBX and MCBXA, underwent acceptance tests at superfluid helium temperature at CERN, before shipping to FNAL for integration in the cold masses. A total of 27 MCBX (Horizontal-Vertical Dipole Correctors), of which 9 MCBXA (with nested Sextupole-Dodecapole insert), are needed for the LHC, including spares. The paper discusses the test protocols for series magnets, and reports the results of quench performance and cold magnetic measurements. The peculiarities of combined training and the hysteresis effects in the nested windings are presented, together with the search of the optimum setting procedure to minimize the persistent current effects on the beam dynamics.

  7. Constraints from muon g-2 and LFV processes in the Higgs Triplet Model

    CERN Document Server

    Fukuyama, Takeshi; Tsumura, Koji


    Constraints from the muon anomalous magnetic dipole moment and lepton flavor violating processes are translated into lower bounds on v_Delta*m_H++ in the Higgs Triplet Model by considering correlations through the neutrino mass matrix. The discrepancy of the sign of the contribution to the muon anomalous magnetic dipole moment between the measurement and the prediction in the model is clarified. It is shown that mu to e gamma, tau decays (especially, tau to mu e e), and the muonium conversion can give a more stringent bound on v_Delta*m_H++ than the bound from mu to eee which is expected naively to give the most stringent one.

  8. Hybrid spin and valley quantum computing with singlet-triplet qubits. (United States)

    Rohling, Niklas; Russ, Maximilian; Burkard, Guido


    The valley degree of freedom in the electronic band structure of silicon, graphene, and other materials is often considered to be an obstacle for quantum computing (QC) based on electron spins in quantum dots. Here we show that control over the valley state opens new possibilities for quantum information processing. Combining qubits encoded in the singlet-triplet subspace of spin and valley states allows for universal QC using a universal two-qubit gate directly provided by the exchange interaction. We show how spin and valley qubits can be separated in order to allow for single-qubit rotations.

  9. Quenching behaviour of quadrupole model magnets for the LHC inner triplets at Fermilab

    CERN Document Server

    Andreev, N; Bauer, P; Bossert, R; Brandt, J; Chichili, D R; Carson, J; Di Marco, J; Fehér, S; Glass, H; Kerby, J S; Lamm, M J; Makarov, A A; Nobrega, A; Novitski, I; Ogitsu, T; Orris, D; Ozelis, J P; Rabehl, Roger Jon; Robotham, W; Sabbi, G L; Schlabach, P; Sylvester, C D; Strait, J B; Tartaglia, M; Tompkins, J C; Yadav, S; Zlobin, A V; Caspi, S; McInturff, A D; Scanlan, R M; Ghosh, A


    The US-LHC Accelerator Project is responsible for the design and production of inner triplet high gradient quadrupoles for installation in the LHC Interaction Region. The quadrupoles are required to deliver a nominal field gradient of 215 T/m in a 70 mm bore, and operate in superfluid helium. As part of the magnet development program, a series of 2 m model magnets have been built and tested at Fermilab, with each magnet being tested over several thermal cycles. This paper summarizes the quench performance and analysis of the model magnets tested, including quench training, and the ramp rate and temperature of the magnet quench current. (7 refs).

  10. Successful triplet pregnancy in an African with pure gonadal dysgenesis:A plus for assisted reproduction

    Institute of Scientific and Technical Information of China (English)

    Aziken M; Osaikhuwuomwan J; Osemwenkha A; Iribhogbe O; Orhue A


    Gonadal dysgenesis represents a congenital developmental disorder of the reproductive system, with its main gynaecologic manifestations being amenorrhea and infertility. We present a unique case of pure gonadal dysgenesis in an ‘about to be’ married lady resident in a society where high premium and success in marriage is dependent on childbirth. With astute evaluation and counseling, assisted reproductive technology (ART) was safely and successfully used in this case with eventual triplet pregnancy and delivery. Our index experience shows that situations with compromised fertility the availability and access to ART aids effective treatment planning and births a re-invigorated hope for family life.

  11. Desempenho comunicativo em trigêmeos prematuros Acquisition and development language in premature triplets

    Directory of Open Access Journals (Sweden)

    Amanda Tragueta Ferreira


    Full Text Available OBJETIVO: descrever habilidades do desenvolvimento de trigêmeos aos 18 meses e aos 29 meses de vida, enfocando a comunicação. MÉTODOS: irmãos trigêmeos dizigóticos do sexo masculino. Os procedimentos de avaliação englobaram: Anamnese, Observação do Comportamento Comunicativo e Escala de Desenvolvimento de Gesell e Amatruda (2000. As avaliações foram realizadas aos 18 e aos 29 meses. As crianças apresentaram atraso do desenvolvimento neuropsicomotor e eram expostas a multilingüismo. RESULTADOS: foi verificada alteração nos comportamentos comunicativos nas três crianças, tanto na primeira quanto na segunda avaliação, embora tenha sido observada melhora do desempenho, após as orientações recebidas pela família. Na segunda avaliação foi observada criptofasia. Dos comportamentos motor grosseiro, delicado, adaptativo, pessoal-social e de linguagem, o último foi o mais afetado para as três crianças, apesar de todos estarem alterados considerando a idade cronológica dos trigêmeos. CONCLUSÃO: as habilidades do desenvolvimento dos trigêmeos avaliados neste estudo estavam alteradas, acometendo todas as áreas. Ressalta-se maior comprometimento da linguagem tanto aos 18 como aos 29 meses.PURPOSE: to describe abilities of triplets' development by 18 months and the 29 months of life, focusing on communication. METHODS: dizygotic male sibling triplets. The evaluation procedures included history of disease, observing the communicative behavior and Escala de Desenvolvimento de Gesell e Amatruda (2000. The evaluations were accomplished by the 18 months and the 29 months. The children showed delay in the neuropshycomotor development and were exposed to multilingualism. RESULTS: alteration was verified in the communicative behaviors in the three children, both in the first as well as in the second evaluation, although an amelioration was shown in the performance, after the orientations received by the family. Cryptophasia was

  12. Successful triplet pregnancy in an African with pure gonadal dysgenesis: A plus for assisted reproduction

    Directory of Open Access Journals (Sweden)

    M Aziken


    Full Text Available Gonadal dysgenesis represents a congenital developmental disorder of the reproductive system, with its main gynaecologic manifestations being amenorrhea and infertility. We present a unique case of pure gonadal dysgenesis in an ‘about to be’ married lady resident in a society where high premium and success in marriage is dependent on childbirth. With astute evaluation and counseling, assisted reproductive technology (ART was safely and successfully used in this case with eventual triplet pregnancy and delivery. Our index experience shows that situations with compromised fertility the availability and access to ART aids effective treatment planning and births a re-invigorated hope for family life.

  13. Finite-bias conductance anomalies at a singlet-triplet crossing

    DEFF Research Database (Denmark)

    Stevanato, Chiara; Leijnse, Martin Christian; Flensberg, Karsten;


    Quantum dots and single-molecule transistors may exhibit level crossings induced by tuning external parameters such as magnetic eld or gate voltage. For Coulomb blockaded devices, this shows up as an inelastic cotunneling threshold in the dierential conductance, which can be tuned to zero...... at the crossing. Here we show that, in addition, level crossings can give rise to a nearly vertical step-edge, ridge or even a Fano-like ridge-valley feature in the dierential conductance inside the relevant Coulomb diamond. We study a gate-tunable quasidegeneracy between singlet and triplet ground states...

  14. Singlet-triplet gaps in substituted carbenes predicted from block-correlated coupled cluster method

    Institute of Scientific and Technical Information of China (English)


    The block correlated coupled cluster (BCCC) method, with the complete active-space self-consistent-field (CASSCF) reference function, has been applied to investigating the singlet-triplet gaps in several substituted carbenes including four halocarbenes (CHCl, CF2, CCl2, and CBr2) and two hydroxycar-benes (CHOH and C(OH)2). A comparison of our results with the experimental data and other theoretical estimates shows that the present approach can provide quantitative descriptions for all the studied carbenes. It is demonstrated that the CAS-BCCC method is a promising theoretical tool for calculating the electronic structures of diradicals.

  15. Inelastic and elastic collision rates for triplet states of ultracold strontium

    CERN Document Server

    Traverso, A; de Escobar, Y N Martinez; Mickelson, P G; Nagel, S B; Yan, M; Killian, T C


    We report measurement of the inelastic and elastic collision rates for ^{88}Sr atoms in the (5s5p)^3P_0 state in a crossed-beam optical dipole trap. This is the first measurement of ultracold collision properties of a ^3P_0 level in an alkaline-earth atom or atom with similar electronic structure. Since the (5s5p)^3P_0 state is the lowest level of the triplet manifold, large loss rates indicate the importance of principle-quantum-number-changing collisions at short range. We also provide an estimate of the collisional loss rates for the (5s5p){^3P_2} state.

  16. Inelastic and elastic collision rates for triplet states of ultracold strontium (United States)

    Traverso, A.; Chakraborty, R.; Martinez de Escobar, Y. N.; Mickelson, P. G.; Nagel, S. B.; Yan, M.; Killian, T. C.


    We report measurement of the inelastic and elastic collision rates for S88r atoms in the (5s5p)P30 state in a crossed-beam optical dipole trap. Since the (5s5p)P30 state is the lowest level of the triplet manifold, large loss rates indicate the importance of principle-quantum-number-changing collisions at short range. We also provide an estimate of the collisional loss rates for the (5s5p)P32 state. Large loss-rate coefficients for both states indicate that evaporative cooling toward quantum degeneracy in these systems is unlikely to be successful.

  17. A Three-loop Neutrino Mass Model with a Colored Triplet Scalar

    CERN Document Server

    Cheung, Kingman; Okada, Hiroshi


    We study a variation of the Krauss-Nasri-Trodden (KNT) model with a colored triplet scalar field and a colored singlet scalar field, in which we discuss the anomaly coming from $b\\to s\\mu\\bar\\mu$, fitting to the muon anomalous magnetic moment and the relic density of the Majorana-type dark matter candidate, as well as satisfying various constraints such as lepton-flavor violations and flavor-changing neutral currents. Also, we discuss the direct constraints from the collider searches and the possibilities of detecting the new fields at the LHC.

  18. Fundamental fermion masses from deformed SU{sub q}(2) triplets

    Energy Technology Data Exchange (ETDEWEB)

    Palladino, B.E.; Ferreira, P.L. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil)


    A spectrum generating q-algebra, within the framework of SU{sub q}(2), is studied in order to describe the mass spectrum of three generations of quarks and leptons. The SU{sub q}(2) quantum group is a q-deformed extension of SU(2), where q=exp{alpha} (with {alpha} real) is the deformation parameter. In this letter, the essential use of inequivalent representations of SU{sub q}(2) is introduced. A formula for the fermion masses is derived. As an example, a possible scheme which corresponds to two triplets associated to up and down quarks is presented here in some detail. 19 refs., 3 tabs.

  19. Higher-order recoil corrections for triplet states of the helium atom

    CERN Document Server

    Patkos, V; Pachucki, K


    Nuclear recoil corrections of order $\\alpha^6\\,m^2/M$ are calculated for the lowest-lying triplet states of the helium atom. It improves the theoretical prediction for the isotope shift of the $2^3S-2^3P$ transition energy and influences the determination of the ${}^3\\textrm{He}-{}^4\\textrm{He}$ nuclear charge radii difference. This calculation is a step forward on the way towards the direct determination of the charge radius of the helium nucleus from spectroscopic measurements.

  20. Field-induced transition from chiral spin-triplet to mixed-parity Fulde-Ferrell-Larkin-Ovchinnikov superconductivity (United States)

    Romano, Alfonso; Cuoco, Mario; Noce, Canio; Gentile, Paola; Annunziata, Gaetano


    We analyze the response to a magnetic field of a two-dimensional spin-triplet superconductor with chiral order parameter when triplet pairing is closely competing with the singlet one. The study is performed via numerical solution of the Bogoliubov-de Gennes equations, assuming that the translational symmetry is broken in one direction by the presence of an interface beyond which superconducting pairing is not effective. We show that as the intensity of the magnetic field is increased above a threshold value, the system undergoes a transition to a spatially inhomogeneous state of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) type where chirality disappears and a singlet-triplet mixing takes place along the direction perpendicular to the interface. Subdominant singlet components are found to accompany the triplet dominant ones in both phases. They develop close to the interface at low fields, then turning continuously into oscillating long-range ones as the field is increased. A similar behavior is found for the magnetization. It nucleates at the interface in the chiral phase, then acquiring in the FFLO phase an oscillatory behavior reaching its maximum amplitude at the sites where the dominant triplet component has a node. At these sites, the local spin-resolved density of states exhibits strong resonances, associated with the formation of Andreev bound states, which tend to broaden and decay in intensity as increasingly high magnetic fields are considered.

  1. Discovery of an extremely gas-rich dwarf triplet near the center of the Lynx-Cancer void

    CERN Document Server

    Chengalur, Jayaram N


    Giant Metrewave Radio Telescope (GMRT) HI observations, done as part of an ongoing study of dwarf galaxies in the Lynx-Cancer void, resulted in the discovery of a triplet of extremely gas rich galaxies located near the centre of the void.The triplet members SDSS J0723+3621, J0723+3622 and J0723+3624 have absolute magnitudes M_B of -14.2, -11.9 and -9.7 and M(HI)/L_B of \\sim 2.9, ~10 and ~25, respectively. The gas mass fractions, as derived from the SDSS photometry and the GMRT data are 0.93, 0.997, 0.997 respectively. The faintest member of this triplet SDSS J0723+3624 is one of the most gas rich galaxies known. We find that all three galaxies deviate significantly from the Tully-Fisher relation, but follow the baryonic Tully-Fisher relation. All three galaxies also have a baryon fraction that is significantly smaller than the cosmic baryon fraction. For the largest galaxy in the triplet, this is in contradiction to numerical simulations. The discovery of this very unique dwarf triplet lends support to the id...

  2. A blocked diketo form of avobenzone: photostability, photosensitizing properties and triplet quenching by a triazine-derived UVB-filter. (United States)

    Paris, Cecilia; Lhiaubet-Vallet, Virginie; Jiménez, Oscar; Trullas, Carles; Miranda, Miguel Angel


    Novel sunscreens are required providing active protection in the UVA and UVB regions. On the other hand, there is an increasing concern about the photosafety of UV filters, as some of them are not sufficiently photostable. Avobenzone is one of the most frequently employed sunscreen ingredients, but it has been reported to partially decompose after irradiation. In the present work, photophysical and photochemical studies on a methylated avobenzone-derivative have shown that the diketo form is responsible for photodegradation. A transient absorption was observed at 380 nm after laser flash photolysis excitation at 308 nm. It was assigned to the triplet excited state of the diketo form, as inferred from quenching by oxygen and beta-carotene. This transient also interacted with key building blocks of biomolecules by triplet-triplet energy transfer (in the case of thymidine) or electron transfer processes (for 2'-deoxyguanosine, tryptophan and tyrosine). Irradiation of the avobenzone derivative in the presence of a triazine UV-B filter (E-35852) diminished the undesirable effects of the compound by an efficient quenching of the triplet excited state. Thus, sunscreen formulations including triplet quenchers could provide effective protection from the potential phototoxic and photoallergic effects derived from poor photostability of avobenzone.

  3. The Kinetics of Joined Action of Triplet-Triplet Annihilation and First-Order Decay of Molecules in T1 State in the Case of Nondominant First-Order Process: The Kinetic Model in the Case of Spatially Periodic Excitation

    Directory of Open Access Journals (Sweden)

    Paweł Borowicz


    Full Text Available In this paper the model developed for estimation of the diffusion coefficient of the molecules in the triplet state is presented. The model is based on the intuitive modification of the Smoluchowski equation for the time-dependent rate parameter. Since the sample is irradiated with the spatially periodic pattern nonexponential effects can be expected in the areas of the constructive interference of the exciting laser beams. This nonexponential effects introduce changes in the observed kinetics of the diffusion-controlled triplet-triplet annihilation. Due to irradiation with so-called long excitation pulse these non-exponential effects are very weak, so they can be described with introducing very simple correction to the kinetic model described in the first paper of this series. The values of diffusion coefficient of anthracene are used to calculate the annihilation radius from the data for spatially homogeneous excitation.

  4. The Free Energy of dsDNA Basepair Triplets Bound to an ssDNA/RecA Filament May be a Non-Linear Function of the Number of Contiguous Bound Triplets

    CERN Document Server

    Feinstein, Efraim; Prentiss, Mara


    The homology search process depends on the free energy of double stranded DNA (dsDNA) triplets bound to pre-synaptic filaments. It has been assumed that the total free energy is a linear function of the number of bound dsDNA triplets. We present an analytical model using a simplified version of the known structure of dsDNA bound to ssDNA/RecA filaments. This model predicts that the mechanical energy stored in dsDNA bound to RecA increases non-linearly with the number of contiguous bound dsDNA triplets. We suggest that the free energy increase for the homology searching state is much more rapid than the increase for the post-strand exchange state and propose that this difference may play a vital role in the homology search/strand exchange process.

  5. Variety of SO(10) GUTs with Natural Doublet-Triplet Splitting via the Missing Partner Mechanism

    CERN Document Server

    Babu, K S; Nath, Pran; Syed, Raza M


    We present a new class of unified SO(10) models where the GUT symmetry breaking down to the standard model gauge group involves just one scale, in contrast to the conventional SO(10) models which require two scales. Further, the models we discuss possess a natural doublet-triplet splitting via the missing partner mechanism without fine tuning. Such models involve $560+\\ov{560}$ pair of heavy Higgs fields along with a set of light fields. The $560+\\ov{560}$ are the simplest representations of SO(10) besides the $126+\\ov{126}$ which contain an excess of color triplets over $SU(2)_L$ doublets. We discuss several possibilities for realizing the missing partner mechanism within these schemes. With the $126+\\ov{126}$ multiplets, three viable models are found with additional fields belonging to ${210 + 2 \\times 10 + 120}$, ${45 + 10 + 120}$, or ${210 + 16 + \\ov{16} + 10 + 120}$. With the $560+\\ov{560}$, a unique possibility arises for the missing partner mechanism, with additional ${2\\times 10+ 320}$ fields. These m...

  6. Triplet generation and upper critical field in superconducting spin valves based on CrO2 (United States)

    Voltan, S.; Singh, A.; Aarts, J.


    It has been recently reported that a superconducting triplet spin valve (TSV) based on the half-metallic CrO2 can show "colossal" variations of the critical temperature, up to more than 1 K. This can be achieved when the magnetic noncollinearity between the mixer (F1) and the drainage ferromagnetic layer (F) is maximized. In this work we investigate further such TSV devices looking at two aspects: first, we present the dependence of the TSV effect on the thickness of the mixer layer; second, we look at the perpendicular upper critical field Hc 2 ⊥ as a function of the temperature. The thickness dependence, which is nonmonotonic as expected, represents a further proof that the effect is due to the generation of equal-spin triplet Cooper pairs, while what we observe for the Hc 2 ⊥ versus T curves is an interesting and peculiar behavior: there is a clear deviation from the universal linear dependence and the average slope is suppressed much more than what can be described with the formalism used for conventional proximized structures.

  7. Expressions of excited states by triplet dimers in heisenberg antiferromagnetic ladders. Analysis of magnetic Raman spectra

    Energy Technology Data Exchange (ETDEWEB)

    Natsume, Yuhei; Tada, Shinichiro; Suzuki, Toshihiko [Chiba Univ., Graduate School of Science and Technology, Chiba (Japan)


    Characteristic properties of excited states in antiferromagnetic ladder systems with spin-1/2 are investigated in relation with the theoretical analysis of the quite asymmetric shape of the peak for twice the spin gap {delta}{sub g} in magnetic Raman spectra. Here, the structure of exchange-scattering spectra are reproduced by the numerical calculation for the finite Heisenberg ladder, in which legs with antiferromagnetic bond J{sub c} is connected by rungs with antiferromagnetic bond J{sub r}. The singlet ground state in this system can be expressed as the ordering of singlet dimers on rungs in the ladder for J{sub c}/J{sub r} {yields} +0. In fact, the value of 0.1 is adopted to be the ratio of J{sub c}/J{sub r} in order to discuss the experimental work of the magnetic Raman spectra for the ladder of V{sup 4+} ions in the oxide compound CaV{sub 2}O{sub 5} reported in Konstantinovic et al., Phys. Rev. B61 (2000), 15185. As for this peak of 2{delta}{sub g}, quite an asymmetric observed shape is explained by the present calculation. According to the analysis of spectra, we discuss the expression of excited states by triplet dimers on rungs: The dominant contribution of the pair of triplet dimers on adjacent rungs to the corresponding state for 2{delta}{sub g} peak is pointed out. (author)

  8. Dark matter versus h→γγ and h→γZ with supersymmetric triplets

    Energy Technology Data Exchange (ETDEWEB)

    Arina, Chiara [Institut d' Astrophysique de Paris, 75 - Paris (France); Martin-Lozano, Victor [Univ. Autonoma de Madrid/CSIC (Spain). Inst. de Fisica Teorica; Universidad Autonoma de Madrid (Spain). Dept. de Fisica Teorica; Nardini, Germano [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Bielefeld Univ. (Germany). Fakultaet fuer Physik


    The Triplet extension of the MSSM (TMSSM) alleviates the little hierarchy problem and provides a significant enhancement of the loop-induced diphoton rate of the lightest CP-even Higgs h. In this paper we pursue the analysis of the TMSSM Higgs phenomenology by computing for the first time the h→Zγ decay. Interestingly we find that the rates of loop-induced decays are correlated and their signal strengths can rise up to 40%-60% depending on the channel. We furthermore study the dark matter phenomenology of the TMSSM. The lightest neutralino is a good dark matter candidate in two regions. The first one is related to the Higgs and Z resonances and the LSP is mostly Bino. The second one is achieved for a mass larger than 90 GeV and the LSP behaves as the well-tempered neutralino. An advantage of the triplet contribution is that the well-tempered neutralino can be a Bino-Triplino mixture, relieving the problem of achieving M{sub 2}∝M{sub 1} in unified scenarios. The dark matter constraints strongly affect the Higgs phenomenology, reducing the potential enhancements of the diphoton and of the Zγ channels by 20% at most. These enhancements are however larger than the MSSM ones. In the near future, complementarity of dark matter direct searches and collider experiments will be crucial to probe most of the parameter space where the neutralino is the dark matter candidate.

  9. Dark Matter versus h into gamma gamma and h into gamma Z with supersymmetric triplets

    CERN Document Server

    Arina, Chiara; Nardini, Germano


    The Triplet extension of the MSSM (TMSSM) alleviates the little hierarchy problem and provides a significant enhancement of the loop-induced diphoton rate of the lightest CP-even Higgs h. In this paper we pursue the analysis of the TMSSM Higgs phenomenology by computing for the first time the h into Z + gamma decay. Interestingly we find that the rates of loop-induced decays are correlated and their signal strengths can rise up to 40% - 60% depending on the channel. We furthermore study the dark matter phenomenology of the TMSSM. The lightest neutralino is a good dark matter candidate in two regions. The first one is related to the Higgs and Z resonances and the LSP is mostly Bino. The second one is achieved for a mass larger than 90 GeV and the LSP behaves as the well-tempered neutralino. An advantage of the triplet contribution is that the well-tempered neutralino can be a Bino-Triplino mixture, relieving the problem of achieving M_2 ~ M_1 in unified scenarios. The dark matter constraints strongly affect th...

  10. Observation of Mollow Triplets with Tunable Interactions in Double Lambda Systems of Individual Hole Spins (United States)

    Lagoudakis, K. G.; Fischer, K. A.; Sarmiento, T.; McMahon, P. L.; Radulaski, M.; Zhang, J. L.; Kelaita, Y.; Dory, C.; Müller, K.; Vučković, J.


    Although individual spins in quantum dots have been studied extensively as qubits, their investigation under strong resonant driving in the scope of accessing Mollow physics is still an open question. Here, we have grown high quality positively charged quantum dots embedded in a planar microcavity that enable enhanced light-matter interactions. Under a strong magnetic field in the Voigt configuration, individual positively charged quantum dots provide a double lambda level structure. Using a combination of above-band and resonant excitation, we observe the formation of Mollow triplets on all optical transitions. We find that when the strong resonant drive power is used to tune the Mollow-triplet lines through each other, we observe anticrossings. We also demonstrate that the interaction that gives rise to the anticrossings can be controlled in strength by tuning the polarization of the resonant laser drive. Quantum-optical modeling of our system fully captures the experimentally observed spectra and provides insight on the complicated level structure that results from the strong driving of the double lambda system.

  11. Rectification and Robust Matching Using Oriented Image Triplets for Minimally Invasive Surgery (United States)

    Conen, N.; Jepping, C.; Luhmann, T.; Maas, H.-G.


    Stereo endoscopes for minimally invasive surgery have been available on the market for several years and are well established in some areas. In practice, they offer a stereoscopic view to the surgeon but are not yet intended for 3D measurements. However, using current knowledge about the camera system and the difficult conditions in object space, it is possible to reconstruct a highly accurate surface model of the current endoscopic view. In particular for medical interventions, a highly reliable point cloud and real-time computation are required. To obtain good reliability, a miniaturised trinocular camera system is introduced that reduces the amount of outliers. To reduce computation time, an approach for generation of rectified image triplets and their corresponding interior and exterior camera parameters has been developed. With these modified and parameterised images it is possible to directly process 3D measurements in object space. Accordingly, an efficient semi-global optimisation is implemented by the authors. In this paper the special camera system, the rectification approach and the applied methodology of matching in rectified image triplets are explained. Finally, first results are presented. In conclusion, the trinocular camera system provides more reliable point clouds than a binocular one, especially for areas with repetitive or poor texture. Currently, the benefit of the third camera is not as great as desired.

  12. A CP-violating phase in a two Higgs triplet scenario : some phenomenological implications

    CERN Document Server

    Chaudhuri, Avinanda


    We consider a scenario where, along with the usual Higgs doublet, two scalar triplets are present. The extension of the triplet sector is required for the Type~II mechanism for the generation of neutrino masses, if this mechanism has to generate a neutrino mass matrix with two-zero texture. One CP-violating phase has been retained in the scalar potential of the model, and all parameters have been chosen consistently with the observed neutrino mass and mixing patterns. We find that a large phase ($\\gtrsim 60^{\\circ}$) splits the two doubly-charged scalar mass eigenstates wider apart, so that the decay $H_1^{++} \\rightarrow H_2^{++} h$ is dominant (with h being the $125$ GeV scalar). We identify a set of benchmark points where this decay dominates. This is complementary to the situation, reported in our earlier work, where the heavier doubly-charged scalar decays as $H_1^{++} \\rightarrow H_2^+ W^+$. We point out the rather spectacular signal, ensuing from $H_1^{++} \\rightarrow H_2^{++} h$, in the form of Higgs ...

  13. Intermolecular electron transfer from naphthalene derivatives in the higher triplet excited states. (United States)

    Sakamoto, Masanori; Cai, Xichen; Hara, Michihiro; Fujitsuka, Mamoru; Majima, Tetsuro


    Intermolecular electron transfer (ELT) from a series of naphthalene derivatives (NpD) in the higher triplet excited states (T(n)) to carbon tetrachloride (CCl(4)) in Ar-saturated acetonitrile was observed using the two-color two-laser flash photolysis method. The ELT efficiency depended on the driving force of ELT. Since the ELT from the T(n) state occurred competitively with the internal conversion (IC, T(n) --> T(1)) and the triplet energy transfer (ENT), the ELT became apparent only when sufficient free energy change of ELT was attained. On the other hand, ELT from the T(1) state was not observed, although ELT from the T(1) state with sufficiently long lifetime has a slightly exothermic driving force. The fast ELT from the T(n) state and lack of the reactivity of the T(1) state were explained well by the "sticky" dissociative electron-transfer model based on one-electron reductive attachment to CCl(4) leading to the C-Cl bond cleavage.

  14. Doublets, triplets, or quadruplets of novel agents in newly diagnosed myeloma? (United States)

    Rajkumar, S Vincent


    The treatment of multiple myeloma is evolving rapidly. A plethora of doublet, triplet, and quadruplet combinations have been studied for the treatment of newly diagnosed myeloma. Although randomized trials have been conducted comparing older regimens such as melphalan-prednisone with newer regimens containing drugs such as thalidomide, lenalidomide, or bortezomib, there are few if any randomized trials that have compared modern combinations with each other. Even in the few trials that have done so, definitive overall survival or patient-reported quality-of-life differences have not been demonstrated. Therefore, there is marked heterogeneity in how newly diagnosed patients with myeloma are treated around the world. The choice of initial therapy is often dictated by availability of drugs, age and comorbidities of the patient, and assessment of prognosis and disease aggressiveness. This chapter reviews the current data on the most commonly used and tested doublet, triplet, and quadruplet combinations for the treatment of newly diagnosed myeloma and provides guidance on choosing the optimal initial treatment regimen.

  15. Filter-filter interactions. Photostabilization, triplet quenching and reactivity with singlet oxygen. (United States)

    Lhiaubet-Vallet, Virginie; Marin, Mireia; Jimenez, Oscar; Gorchs, Olga; Trullas, Carles; Miranda, Miguel Angel


    In most sunscreens, the presence of two UV filters usually leads to synergistic effects regarding both the final performance and photostabilization of the active principles. However, this may also result in an accelerated decomposition if a photoreaction occurs between the single components. Thus, the understanding of photophysics and photochemistry of UV filter combinations is important to improve sunscreen photostability. In this context, photoreactivity of a commonly used UVA filter, namely tert-butylmethoxydibenzoylmethane (BM-DBM, also known as avobenzone, Parsol 1789, etc.), has been studied in the presence of six commercial solar filters: octyl methoxycinnamate, bis-ethylhexyloxyphenol methoxyphenyl triazine, octocrylene, diethylamino hydroxybenzoyl hexyl benzoate, octyl triazone and dioctyl butamido triazone. To achieve this goal, a mechanism-based strategy has been designed in order to investigate the photostability of sunscreens in a more systematic way, taking into account different processes: tautomerization of BM-DBM, formation of triplet excited state of BM-DBM in its diketo form and its quenching in the presence of UV filters, reactivity of UV filters under triplet photosensitization, quenching of singlet oxygen by UV filters and degradation of the latter under singlet oxygenation conditions.

  16. The Chemical Enrichment History of the Fornax Dwarf Spheroidal Galaxy from the Infrared Calcium Triplet

    CERN Document Server

    Pont, F; Gallart, C; Hardy, E; Winnick, R A; Pont, Frederic; Zinn, Robert; Gallart, Carme; Hardy, Eduardo; Winnick, Rebeccah


    Near infrared spectra were obtained for 117 red giants in the Fornax dwarf spheroidal galaxy with the FORS1 spectrograph on the VLT, in order to study the metallicity distribution of the stars and to lift the age-metallicity degeneracy of the red giant branch (RGB) in the color-magnitude diagram (CMD). Metallicities are derived from the equivalent widths of the infrared Calcium triplet lines at 8498, 8542, and 8662 A, calibrated with data from globular clusters, the open cluster M67 and the LMC. For a substantial portion of the sample, the strength of the Calcium triplet is unexpectedly high, clearly indicating that the main stellar population of Fornax is significantly more metal-rich than could be inferred from the position of its RGB in the CMD. We show that the relative narrowness of the RGB in Fornax is caused by the superposition of stars of very different ages and metallicities. The metallicity distribution in Fornax is centered at [Fe/H]= -0.9, with a metal-poor tail extending to [Fe/H] ~= -2. While t...

  17. Efficient Hybrid White Organic Light-Emitting Diodes for Application of Triplet Harvesting with Simple Structure

    CERN Document Server

    Hwang, Kyo Min; Lee, Sungkyu; Yoo, Han Kyu; Baek, Hyun Jung; Kim, Jwajin; Yoon, Seung Soo; Kim, Young Kwan


    In this study, we fabricated hybrid white organic light-emitting diodes (WOLEDs) based on triplet harvesting with simple structure. All the hole transporting material and host in emitting layer (EML) of devices were utilized with same material by using N,N'-di-1-naphthalenyl-N,N'-diphenyl-[1,1':4',1":4",1"'-quaterphenyl]-4,4"'-diamine (4P-NPD) which were known to be blue fluorescent material. Simple hybrid WOLEDs were fabricated three color with blue fluorescent and green, red phosphorescent materials. We was investigated the effect of triplet harvesting (TH) by exciton generation zone on simple hybrid WOLEDs. Characteristic of simple hybrid WOLEDs were dominant hole mobility, therefore exciton generation zone was expected in EML. Additionally, we was optimization thickness of hole transporting layer and electron transporting layer was fabricated a simple hybrid WOLEDs. Simple hybrid WOLED exhibits maximum luminous efficiency of 29.3 cd/A and maximum external quantum efficiency of 11.2%. Commission Internatio...

  18. Preliminary Design of the HiLumi-LHC Triplet Area Beam Screen

    CERN Document Server

    Kersevan, R; Kos, N


    The so-called beam screen (BS) is a proven solution for intercepting the thermal loads caused by the circulating beams in the cryogenically-cooled sections of the LHC and minimizing dynamic vacuum effects [1]. The new triplet area foreseen for the HiLumi-LHC (HL-LHC) machine upgrade [2] has the additional feature of needing internal tungsten shields to reduce the amount of collision debris which is deflected by the high-gradient triplet magnets towards the superconducting magnets' cold masses and coils. The very aggressive optics design, based on large beam separations, calls for a maximum of physical space to remain available to the counter rotating beams in the common BS. This places severe constraints to the fabrication and installation tolerances of the BS itself, in addition to affecting the design and routing of the cryogenic lines in the area. The latest version of the BS design will be shown and discussed, together with future plans for testing materials, fabrication procedures, and installation.

  19. A practical O(n log2 n) time algorithm for computing the triplet distance on binary trees

    DEFF Research Database (Denmark)

    Sand, Andreas; Pedersen, Christian Nørgaard Storm; Mailund, Thomas


    The triplet distance is a distance measure that compares two rooted trees on the same set of leaves by enumerating all sub-sets of three leaves and counting how often the induced topologies of the tree are equal or different. We present an algorithm that computes the triplet distance between two...... rooted binary trees in time O (n log2 n). The algorithm is related to an algorithm for computing the quartet distance between two unrooted binary trees in time O (n log n). While the quartet distance algorithm has a very severe overhead in the asymptotic time complexity that makes it impractical compared...... to O (n2) time algorithms, we show through experiments that the triplet distance algorithm can be implemented to give a competitive wall-time running time....

  20. Third-order spontaneous parametric down-conversion in thin optical fibers as a photon-triplet source

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Maria [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico); Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2732, BC 22860 Ensenada (Mexico); Garay-Palmett, Karina; U' Ren, Alfred B. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico)


    We study the third-order spontaneous parametric down-conversion (TOSPDC) process, as a means to generate entangled photon triplets. Specifically, we consider thin optical fibers as the nonlinear medium to be used as the basis for TOSPDC in configurations where phase matching is attained through the use of more than one fiber transverse modes. Our analysis in this paper, which follows from our earlier paper [Opt. Lett. 36, 190-192 (2011)], aims to supply experimentalists with the details required in order to design a TOSPDC photon-triplet source. Specifically, our analysis focuses on the photon triplet state, on the rate of emission, and on the TOSPDC phase-matching characteristics for the cases of frequency-degenerate and frequency nondegenerate TOSPDC.

  1. Influence of the Paschen-Back effect on the results of polarimetric inversions of the He I 10830 Å triplet (United States)

    Sasso, C.; Lagg, A.; Solanki, S. K.; Socas-Navarro, H.

    The He I triplet at 10830 Å has a great potential for determining the magnetic field vector in the upper chromosphere. The triplet is Zeeman sensitive (Landé factors 2.0, 1.75 and 1.25) and shows the signature of the Hanle effect under appropriate conditions. Additionally, the Zeeman sublevels are influenced by the Paschen-Back effect leading to changes in strength and in position of the Zeeman components of the transitions forming the triplet. In this work we calculate the influence of the Paschen-Back effect on the Stokes profiles and investigate its relevance to inversions on spectro-polarimetric data obtained with the Tenerife Infrared Polarimeter (TIP) at the German Vacuum Tower Telescope (VTT).

  2. Forbidden Electronic Transitions between the Singlet Ground State and the Triplet Excited State of Pt(II) Complexes. (United States)

    Zheng, Greg Y.; Rillema, D. Paul; DePriest, Jeff; Woods, Clifton


    Direct access to the triplet emitting state from the ground state is observed for Pt(II) complexes containing heterocyclic (CwedgeC', CwedgeN, NwedgeN') and bis(diphenylphosphino)alkane (PwedgeP') ligands. Extinction coefficients for such transitions are in the range 4-25 M(-)(1) cm(-)(1). Emission quantum yields resulting from singlet-to-triplet excitation are as high as 61-77 times the emission quantum yields resulting from singlet-to-singlet excitation at 296 K. The intersystem crossing quantum yield from the singlet excited state to triplet emitting state is lower than 2% at 296 K but is greatly enhanced at 77 K. The forbidden electronic transition observed for Pt(II) complexes is attributed to result from spin-orbit coupling due to the presence of Pt(II) in the skeleton structure. The importance of excitation spectra on the computation of emission quantum yields is discussed.

  3. J-state interference signatures in the Second Solar Spectrum: Modeling the Cr I triplet at 5204-5208 A

    CERN Document Server

    Smitha, H N; Stenflo, J O; Bianda, M; Sampoorna, M; Ramelli, R; Anusha, L S


    The scattering polarization in the solar spectrum is traditionally modeled with each spectral line treated separately, but this is generally inadequate for multiplets where J-state interference plays a significant role. Through simultaneous observations of all the 3 lines of a Cr I triplet, combined with realistic radiative transfer modeling of the data, we show that it is necessary to include J-state interference consistently when modeling lines with partially interacting fine structure components. Polarized line formation theory that includes J-state interference effects together with partial frequency redistribution for a two-term atom is used to model the observations. Collisional frequency redistribution is also accounted for. We show that the resonance polarization in the Cr I triplet is strongly affected by the partial frequency redistribution effects in the line core and near wing peaks. The Cr I triplet is quite sensitive to the temperature structure of the photospheric layers. Our complete frequency...

  4. Transport and noise properties of a normal metal-superconductor-normal metal junction with mixed singlet and chiral triplet pairings (United States)

    Paul, Ganesh C.; Dutta, Paramita; Saha, Arijit


    We study transport and zero frequency shot noise properties of a normal metal-superconductor-normal metal (NSN) junction, with the superconductor having mixed singlet and chiral triplet pairings. We show that in the subgapped regime when the chiral triplet pairing amplitude dominates over that of the singlet, a resonance phenomena emerges out at zero energy where all the quantum mechanical scattering probabilities acquire a value of 0.25. At the resonance, crossed Andreev reflection mediating through such junction, acquires a zero energy peak. This reflects as a zero energy peak in the conductance as well depending on the doping concentration. We also investigate shot noise for this system and show that shot noise cross-correlation is negative in the subgapped regime when the triplet pairing dominates over the singlet one. The latter is in sharp contrast to the positive shot noise obtained when the singlet pairing is the dominating one.

  5. Lepton Flavour Violating Decays tau to lll and mu to e gamma in the Higgs Triplet Model

    CERN Document Server

    Akeroyd, A G; Sugiyama, Hiroaki


    Singly and doubly charged Higgs bosons in the Higgs Triplet Model mediate the lepton flavour violating (LFV) decays tau to \\bar{l}ll and mu to e gamma. The LFV decay rates are proportional to products of two triplet Yukawa couplings (h_{ij}) which can be expressed in terms of the parameters of the neutrino mass matrix and an unknown triplet vacuum expectation value. We determine the parameter space of the neutrino mass matrix in which a signal for tau to \\bar{l}ll and/or mu to e gamma is possible at ongoing and planned experiments. The conditions for respecting the stringent upper limit for mu to eee are studied in detail, with emphasis given to the possibility of |h_{ee}|\\simeq 0 which can only be realized if Majorana phases are present.

  6. The magnetic field configuration of a solar prominence inferred from spectropolarimetric observations in the He I 10830 A triplet

    CERN Document Server

    Suárez, David Orozco; Bueno, Javier Trujillo


    Context: The determination of the magnetic field vector in quiescent solar prominences is possible by interpreting the Hanle and Zeeman effects in spectral lines. However, observational measurements are scarce and lack high spatial resolution. Aims: To determine the magnetic field vector configuration along a quiescent solar prominence by interpreting spectropolarimetric measurements in the He I 1083.0 nm triplet obtained with the Tenerife Infrared Polarimeter installed at the German Vacuum Tower Telescope of the Observatorio del Teide. Methods. The He I 1083.0 nm triplet Stokes profiles are analyzed with an inversion code that takes into account the physics responsible of the polarization signals in this triplet. The results are put into a solar context with the help of extreme ultraviolet observations taken with the Solar Dynamic Observatory and the Solar Terrestrial Relations Observatory satellites. Results: For the most probable magnetic field vector configuration, the analysis depicts a mean field streng...

  7. Implications of a Electroweak Triplet Scalar Leptoquark on the Ultra-High Energy Neutrino Events at IceCube

    CERN Document Server

    Mileo, Nicolas; Szynkman, Alejandro


    We study the production of scalar leptoquarks at IceCube, in particular, a particle transforming as a triplet under the weak interaction. The existence of electroweak-triplet scalars is highly motivated by models of grand unification and also within radiative seesaw models for neutrino mass generation. In our framework, we extend the Standard Model by a single colored electroweak-triplet scalar leptoquark and analyze its implications on the excess of ultra-high energy neutrino events observed by the IceCube collaboration. We consider only couplings between the leptoquark to first generation leptons and quarks and carry out a statistical analysis to determine the parameters that best describe the IceCube data as well as set $95\\%$ CL upper bounds. We analyze whether this study is still consistent with most up-to-date LHC data and various low energy observables.

  8. Electron Spectroscopy (United States)

    Siegbahn, Kai

    Wilhelm Conrad Röntgen's discovery of X radiation in 1895 in Wörzburg resulted in an immediate break-through not only in physics but also in Society, the latter mainly because of its sensational radiological applications. Within a short time it furthermore indirectly led to the discovery of radioactivity by Henri Becquerel. The discovery of X radiation opened the gate to modern atomic physics, and radioactivity to nuclear physics. Later on, the discovery of X-ray diffraction by Laue, Friedrich and Knipping in 1912 initiated the field of X-ray spectroscopy with its fundamental contributions to atomic and crystal structures. Secondary electrons were early observed in the scattered radiation when X-rays were hitting a sample. The development of the corresponding electron spectroscopy had to wait a much longer time for its maturity. A survey of electron spectroscopy is presented.

  9. Modern Spectroscopy (United States)

    Barrow, Gordon M.


    Presents the basic ideas of modern spectroscopy. Both the angular momenta and wave-nature approaches to the determination of energy level patterns for atomic and molecular systems are discussed. The interpretation of spectra, based on atomic and molecular models, is considered. (LC)

  10. Bioimpedance Spectroscopy

    DEFF Research Database (Denmark)

    Klösgen, Beate; Rümenapp, Christine; Gleich, Bernhard


    causes relaxation processes with characteristic contributions to the frequency-dependent complex dielectric constant. These dipolar relaxations were initially described by Debye (Polare Molekeln 1929). They are the basis of impedance spectroscopy (K’Owino and Sadik Electroanalysis 17(23):2101–2113, 2005...

  11. Synthesis, measurements, and theoretical analysis of carbazole derivatives with high-triplet-energy

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianli; Mi Xiaoyun; Wan Yuchun [School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Si Zhenjun, E-mail: [School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6 16610 (Czech Republic); Sun Haiying; Duan Qian [School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022 (China); He Xingquan [School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Yan Dong; Wan Sha [School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022 (China)


    In order to obtain the blue light-emitting organic materials with high triplet state energy, two 3,5-diphenyl-4H-1,2,4-triazole (Tz) containing carbazole (Cz) derivatives of 9-(4-(3,5-diphenyl-4H-1,2,4-triazol-4-yl)phenyl)-9H-carbazole (TzCz1) and 3,6-di-tert-butyl-9-(4-(3,5-diphenyl-4H-1,2,4-triazol-4-yl)phenyl) -9H-carbazole (TzCz2) are synthesized using Cz acting as the starting material, as well as characterized by the {sup 1}H NMR spectra, ultraviolet-visible (UV-vis) absorption spectra, and the IR absorption spectra. The luminescence quantum yields (LQYs) of TzCz1 and TzCz2 are measured in CH{sub 2}Cl{sub 2} solution to be 32.1% and 47.5%, respectively. The electrochemical analysis and the photophysical measurements suggest that the triplet energy levels and the energy gaps of the highest-occupied orbital and the lowest-unoccupied orbital are 2.83 eV and 3.59 eV for TzCz1, and 2.80 eV and 3.43 eV for TzCz2. At last, the theoretical analyses of their ground state geometries and the simulated UV-vis absorption spectra are carried out at B3LYP1/6-31G Low-Asterisk level. The studies mentioned above indicate that both TzCz1 and TzCz2 are suitable for the host materials of blue light-emitting diodes. - Highlights: Black-Right-Pointing-Pointer Synthesis of two blue light-emitting Carbazole derivatives. Black-Right-Pointing-Pointer Photophysical and electrochemical properties are systematically studied. Black-Right-Pointing-Pointer Theoretical analysis of geometry of the ground states and the UV-vis absorption are performed with Firefly package. Black-Right-Pointing-Pointer The triplet energy levels are measured to be ca. 2.83 eV.

  12. On the doublet/triplet splitting and intermediate mass scales in locally supersymmetric SO(10) (United States)

    Pulido, João


    In the light of the doublet/triplet splitting, the possibilities for an intermediate mass scale in locally supersymmetric SO(10) are analysed. It is found that the subgroup SU(4)c × SU(2)L × SU(2)R and more generally left-right symmetric models are unlikely to survive as intermediate symmetries since they imply too large values of the weak mixing angle. An alternative model using the subgroup SU(3)c × U(1)L × U(1)R is discussed. Requirements from global SUSY preservation impose an extra constraint and predictions for the grand unification and the intermediate masses are obtained at MX ~ 6 × 1015 GeV and MI ~ 1012 GeV. Address after March 1984: Centro de Fisica da Materia Condensada, Av. Prof. Gama Pinto, 2, 1699 Lisbon Codex, Portugal.

  13. Direct optical access to the triplet manifold of states in H2 (United States)

    Jungen, Ch.; Glass-Maujean, M.


    A number of unassigned lines in the absorption spectrum of diatomic hydrogen are attributed to nominally forbidden transitions from the ground state to the n f manifold of states (Rydberg electron with ℓ =3 orbital momentum). They appear via weak ℓ - mixing interactions leading to local level perturbations. Our analysis is based on multichannel quantum defect theory and uses known theoretical information from the literature. The upper levels of most of these transitions are known to give rise to molecular fluorescence, and they are shown to be singlet-triplet mixed. We conclude that the well-known metastable c 3Πu- state can be populated via one-photon absorption of uv photons followed by cascade emission 4 f →3 d →2 p .

  14. Singlet-triplet gaps in substituted carbenes predicted from block-correlated coupled cluster method

    Institute of Scientific and Technical Information of China (English)

    SHEN Jun; FANG Tao; LI Shuhua


    Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, ChinaThe block correlated coupled cluster (BCCC) method, with the complete active-space self-consistent-field (CASSCF) reference function, has been applied to investigating the singlet-triplet gaps in several substituted carbenes including four halocarbenes (CHCl, CF2, CCl2, and CBr2) and two hydroxycar-bones (CHOH and C(OH)2). A comparison of our results with the experimental data and other theoretical estimates shows that the present approach can provide quantitative descriptions for all the studied carbenes. It is demonstrated that the CAS-BCCC method is a promising theoretical tool for calculating the electronic structures of diradicals.

  15. Spin supercurrent and phase-tunable triplet Cooper pairs via magnetic insulators (United States)

    Gomperud, Ingvild; Linder, Jacob


    We demonstrate theoretically that a dissipationless spin current can flow a long distance through a diffusive normal metal by using superconductors interfaced with magnetic insulators. The magnitude of this spin supercurrent is controlled via the magnetization orientation of the magnetic insulators. The spin supercurrent obtained in this way is conserved in the normal metal just like the charge current and interestingly has a term that is independent of the superconducting phase difference. The quantum state of the system can be switched between 0 and π by reversing the insulators from a parallel to antiparallel configuration with an external field. We show that the spin current is carried through the normal metal by superconducting triplet (odd-frequency) correlations and that the superconducting phase difference can be used to enhance these, leaving clear spectroscopic fingerprints in the density of states.

  16. Transient photocurrent in molecular junctions: singlet switching on and triplet blocking. (United States)

    Petrov, E G; Leonov, V O; Snitsarev, V


    The kinetic approach adapted to describe charge transmission in molecular junctions, is used for the analysis of the photocurrent under conditions of moderate light intensity of the photochromic molecule. In the framework of the HOMO-LUMO model for the single electron molecular states, the analytic expressions describing the temporary behavior of the transient and steady state sequential (hopping) as well as direct (tunnel) current components have been derived. The conditions at which the current components achieve their maximal values are indicated. It is shown that if the rates of charge transmission in the unbiased molecular diode are much lower than the intramolecular singlet-singlet excitation/de-excitation rate, and the threefold degenerated triplet excited state of the molecule behaves like a trap blocking the charge transmission, a possibility of a large peak-like transient switch-on photocurrent arises.

  17. Evidence for spin-triplet superconducting correlations in metal-oxide heterostructures with noncollinear magnetization (United States)

    Khaydukov, Yu. N.; Ovsyannikov, G. A.; Sheyerman, A. E.; Constantinian, K. Y.; Mustafa, L.; Keller, T.; Uribe-Laverde, M. A.; Kislinskii, Yu. V.; Shadrin, A. V.; Kalaboukhov, A.; Keimer, B.; Winkler, D.


    Heterostructures composed of ferromagnetic La0.7Sr0.3MnO3, ferromagnetic SrRuO3, and superconducting YBa2Cu3O6+x were studied experimentally. Structures of composition Au /La0.7Sr0.3MnO3/SrRuO3/YBa2Cu3O6+x were prepared by pulsed laser deposition, and their high quality was confirmed by x-ray diffraction and reflectometry. A noncollinear magnetic state of the heterostructures was revealed by means of superconducting quantum interference device magnetometry and polarized neutron reflectometry. We have further observed superconducting currents in mesa structures fabricated by deposition of a second superconducting Nb layer on top of the heterostructure, followed by patterning with photolithography and ion-beam etching. Josephson effects observed in these mesa structures can be explained by the penetration of a triplet component of the superconducting order parameter into the magnetic layers.

  18. Study of Kapton insulated superconducting coils manufactured for the LHC inner triplet model magnets at Fermilab

    CERN Document Server

    Andreev, N; Bossert, R; Brandt, J; Chichili, D R; Kerby, J S; Nobrega, A; Novitski, I; Ozelis, J P; Yadav, S; Zlobin, A V


    Fermilab has constructed a number of 2 m model quadrupoles as part of an ongoing program to develop and optimize the design of quadrupoles for the LHC Interaction Region inner triplets. The quadrupole design is based upon a two layer shell type coil of multi-filament NbTi strands in Rutherford cable, insulated with Kapton film. As such, the coil size and mechanical properties are critical in achieving the desired prestress and field quality targets for the agent. Throughout the model magnet program, different design and manufacturing techniques have been studied to obtain coils with the required mechanical properties. This paper summarizes the structural material and coil mechanical properties, coil design optimization results and production experience accumulated in the model R&D program. (5 refs).

  19. New 2D Thermal Model Applied to an LHC Inner Triplet Quadrupole Magnet

    CERN Document Server

    Bielert, ER; Ten Kate, HHJ; Verweij, AP


    A newly developed numerical model is presented that enables to compute two-dimensional heat transfer and temperature distributions over the cross-section of superconducting accelerator magnets. The entire thermal path from strand-in-cable to heat sink, including helium channels is considered. Superfluid helium properties are combined with temperature- and field-dependent non-linear solid material properties. Interfacial interactions are also taken into account. The model is applied to the cross-section of an inner triplet quadrupole magnet featuring a new concept for the ground insulation. Beam loss profiles are implemented as main heat source. It is concluded that operational margins can be considerably increased by opening additional thermal paths, improving the cooling conditions.

  20. Metal Abundance Calibration of the Ca II Triplet Lines in RR Lyrae Stars

    CERN Document Server

    Wallerstein, George; Huang, Wenjin


    The GAIA satellite is likely to observe thousands of RR Lyrae stars within a small spectral window, between 8470A and 8750A, at a resolution of 11,500. In order to derive the metallicity of RR Lyrae stars from Gaia, we have obtained numerous spectra of RR Lyrae stars at a resolution of 35,000 with the Apache Point Observatory 3.5 m echelle spectrograph. We have correlated the Ca II triplet line strengths with metallicity as derived from Fe II abundances, analogous to Preston's (1959) use of the Ca II K line to estimate the metallicity of RR Lyrae stars. The Ca II line at 8498A is the least blended with neighboring Paschen lines and thus provides the best correlation.

  1. Single Production of Doubly Charged Higgs Boson via e7 Collision in Higgs Triplet Model

    Institute of Scientific and Technical Information of China (English)

    苏雪松; 岳崇兴; 张娇; 王珏


    The Higgs triplet model (HTM) predicts the existence of a pair of doubly charged Higgs bosons H±±. Single production of H±± via e7 collision at the next generation e+ e- International Linear Collider (ILC) and the Large Hadron electron Collider (LHeC) is considered. The numerical results show that the production cross sections are very sensitive to the neutrino oscillation parameters. Their values for the inverted hierarchy mass spectrum are larger than those for the normal hierarchy mass spectrum at these two kinds of collider experiments. With reasonable values of the relevant free parameters, the possible signals of the doubly charged Higgs bosons predicted by the HTM might be detected in future ILC experiments.

  2. Assessment and Mitigation of the Proton-Proton Collision Debris Impact on the FCC Triplet

    CERN Document Server

    Besana, Maria Ilaria; Fartoukh, Stephane; Martin, Roman; Tomás, Rogelio


    The Future Circular hadron Collider (FCC-hh), which is designed to operate at a centre-of-mass energy of 100 TeV and to deliver ambitious targets in terms of both instantaneous and integrated luminosity, poses extreme challenges in terms of machine protection during operation and with respect to long-term damages. Energy deposition studies are a crucial ingredient for its design. One of the relevant radiation sources are collision debris particles, which de- posit their energy in the interaction region elements and in particular in the superconducting magnet coils of the final focus triplet quadrupoles, to be protected from the risk of quenching and deterioration. In this contribution, the collision debris will be characterised and expectations obtained with FLUKA will be presented, including magnet lifetime considerations. New techniques including crossing angle gymnastics for peak dose deposition mitigation (as recently introduced in the framework of the LHC operation), will be discussed.

  3. A novel SAR fusion image segmentation method based on triplet Markov field (United States)

    Wang, Jiajing; Jiao, Shuhong; Sun, Zhenyu


    Markov random field (MRF) has been widely used in SAR image segmentation because of the advantage of directly modeling the posterior distribution and suppresses the speckle on the influence of the segmentation result. However, when the real SAR images are nonstationary images, the unsupervised segmentation results by MRF can be poor. The recent proposed triplet Markov field (TMF) model is well appropriate for nonstationary SAR image processing due to the introduction of an auxiliary field which reflects the nonstationarity. In addition, on account of the texture features of SAR image, a fusion image segmentation method is proposed by fusing the gray level image and texture feature image. The effectiveness of the proposed method in this paper is demonstrated by a synthesis SAR image and the real SAR images segmentation experiments, and it is better than the state-of-art methods.

  4. Postpartum seizures with posterior reversible encephalopathy syndrome following cesarean delivery for triplets

    Directory of Open Access Journals (Sweden)

    Anita Chhabra


    Full Text Available Posterior reversible encephalopathy syndrome (PRES is a recently described clinicoradiologic entity that is associated with several medical conditions like hypertensive encephalopathy and eclampsia. It presents with rapid onset of symptoms including headache, seizures, altered consciousness, and visual disturbance. It is often, but not always associated with high blood pressure. We present a case of 23-year-old patient, with unremarkable antenatal period, who developed convulsions in the immediate postpartum period following elective cesarean delivery of her triplets performed under regional anesthesia. The magnetic resonance imaging brain revealed vasogenic edema suggestive of PRES. She was managed with supportive treatment including mechanical ventilation in the intensive care unit. She recovered completely without neurological sequelae and discharged on the 8 th postoperative day. This case report highlights the importance of awareness, prompt diagnosis and treatment to improve the outcome in this potentially life-threatening, but reversible condition.

  5. Phototransformation of pesticides in prairie potholes: effect of dissolved organic matter in triplet-induced oxidation. (United States)

    Karpuzcu, M Ekrem; McCabe, Andrew J; Arnold, William A


    Photochemical reactions involving a variety of photosensitizers contribute to the abiotic transformation of pesticides in prairie pothole lakes (PPLs). Despite the fact that triplet excited state dissolved organic matter (DOM) enhances phototransformation of pesticides by acting as a photosensitizer, it may also decrease the overall phototransformation rate through various mechanisms. In this study, the effect of DOM on the phototransformation of four commonly applied pesticides in four different PPL waters was investigated under simulated sunlight using photoexcited benzophenone-4-carboxylate as the oxidant with DOM serving as an anti-oxidant. For atrazine and mesotrione, a decrease in phototransformation rates was observed, while phototransformations of metolachlor and isoproturon were not affected by DOM inhibition. Phototransformation rates and the extent of inhibition/enhancement by DOM varied spatially and temporally across the wetlands studied. Characterization of DOM from the sites and different seasons suggested that the DOM type and variations in the DOM structure are important factors controlling phototransformation rates of pesticides in PPLs.

  6. Measurements of Ca II Infrared Triplet Lines of Young Stellar Objects

    CERN Document Server

    Moto'oka, Keiko


    Equivalent widths and line widths of Ca II infrared triplet emission lines were measured in high-resolution optical spectra of 39 young stellar objects.We found that the equivalent widths of the emission lines decrease with stellar evolution. It has been often claimed that strong chromospheric activity is generated by a dynamo process caused by fast rotation of the photosphere. However, we found no clear correlation between the strength of the Ca II lines and the stellar rotation velocity. Instead, we found that the objects with high mass accretion rates had stronger Ca II emission lines. This correlation supports the turbulent chromosphere model or the magnetic accretion theory for classical T Tauri stars. We also noticed that the equivalent widths of Ca II lines of transitional disk objects are one-tenth of those of classical T Tauri stars, even if the masses of the circumstellar disks are comparable.

  7. 750-GeV Diphoton Resonance as the Singlet of Custodial Higgs Triplet Model

    CERN Document Server

    Chiang, Cheng-Wei


    The observation of diphoton excess around the mass of 750~GeV at the LHC motivates us to consider the singlet Higgs boson in the custodial Higgs triplet model as a good candidate. Based on an earlier study of comprehensive parameter scan for viable mass spectra, we show that the diphoton resonance data fall well within the allowed space. Moreover, we point out that a definite mass hierarchy emerges among the exotic Higgs bosons in the model. Further search channels for the singlet and those for the other exotic Higgs bosons in LHC Run-II are discussed. In particular, we present a simulation of distributions of two kinematic variables for the search of the doubly-charged Higgs boson.

  8. Area-dependence of spin-triplet supercurrent in ferromagnetic Josephson junctions (United States)

    Wang, Yixing; Pratt, W. P., Jr.; Birge, Norman O.


    Josephson junctions containing multiple ferromagnetic layers can carry spin-triplet supercurrent under certain conditions. Large-area junctions containing multiple domains are expected to have a random distribution of 0 or π coupling across the junction surface, whereas magnetized samples should have uniquely π coupling everywhere. We have measured the area-dependence of the critical current in such junctions, and confirm that the critical current scales linearly with area in magnetized junctions. For as-grown (multidomain) samples, the results are mixed. Samples grown on a thick Nb base exhibit critical currents that scale sublinearly with area, while samples grown on a smoother Nb/Al multilayer base exhibit critical currents that scale linearly with area. The latter results are consistent with a theoretical picture due to Zyuzin and Spivak that predicts that the as-grown samples should have global π/2 coupling.

  9. Monozygotic Triplets and Dizygotic Twins following Transfer of Three Poor-Quality Cleavage Stage Embryos

    Directory of Open Access Journals (Sweden)

    Reshef Tal


    Full Text Available Background. Assisted reproductive technology has been linked to the increased incidence of monozygotic twinning. It is of clinical importance due to the increased risk of complications in multiple pregnancies in general and in monozygotic twins in particular. Case. A 29-year-old female, nulligravida underwent her first IVF cycle. Three poor-quality cleavage stage embryos were transferred resulting in monochorionic triamniotic triplets and dichorionic diamniotic twins. Selective embryo reduction was performed at 12 weeks leaving dichorionic twins. The patient underwent emergency cesarean section due to preterm labor and nonreassuring fetal heart tracing at 30 weeks of gestation. Conclusion. Our case emphasizes that even embryos with significant morphological abnormalities should be considered viable and the possibility of simultaneous spontaneous embryo splitting must be factored into determining number of embryos to transfer.

  10. Radiative corrections to the Higgs boson couplings in the Higgs triplet model

    CERN Document Server

    Kikuchi, Mariko


    We calculate Higgs coupling constants at one-loop level in the Higgs triplet model (HTM) to compare to future collider experiments. We evaluate the decay rate of the standard model (SM)-like Higgs boson ($h$) into diphoton. Renormalized Higgs couplings with the weak gauge bosons $hVV$ ($V=W$\\ and\\ $Z$) and the trilinear coupling $hhh$ are also calculated at the one-loop level in the on-shell scheme. The event rate of the $pp\\rightarrow h \\rightarrow \\gamma\\gamma$ channel in the HTM to the one in the SM can cover the value from the recent LHC data. We find that in the allowed parameter region by the current data, deviations in the one-loop corrected $hVV$ and $hhh$ vertices can be about -1% and +50%, respectively. Magnitudes of these deviations can be enough significant to compare with the precision future data at the International Linear Collider.

  11. The Scalar Triplet Contribution to Lepton Flavour Violation and Neutrinoless Double Beta Decay in Left-Right Symmetric Model

    CERN Document Server

    Bambhaniya, Gulab; Goswami, Srubabati; Mitra, Manimala


    We analyse in detail the scalar triplet contribution to the low-energy lepton flavour violating (LFV) and lepton number violating (LNV) processes within a TeV-scale left-right symmetric framework. We show that in both type-I and type-II seesaw dominance for the light neutrino masses, the triplet of comparable or smaller mass than the largest right-handed neutrino mass scale can give sizeable contribution to the LFV processes, except in the quasi-degenerate limit of light neutrino masses, where a suppression can occur due to cancellations. In particular, a moderate value of the heaviest neutrino to scalar triplet mass ratio $r\\lesssim {\\cal O}(1)$ is still experimentally allowed and can be explored in the future LFV experiments. Similarly, the contribution of a relatively light triplet to the LNV process of neutrinoless double beta decay could be significant, disfavouring a part of the model parameter space otherwise allowed by LFV constraints. Nevertheless, we find regions of parameter space consistent with b...

  12. Triplet vs doublet lenalidomide-containing regimens for the treatment of elderly patients with newly diagnosed multiple myeloma. (United States)

    Magarotto, Valeria; Bringhen, Sara; Offidani, Massimo; Benevolo, Giulia; Patriarca, Francesca; Mina, Roberto; Falcone, Antonietta Pia; De Paoli, Lorenzo; Pietrantuono, Giuseppe; Gentili, Silvia; Musolino, Caterina; Giuliani, Nicola; Bernardini, Annalisa; Conticello, Concetta; Pulini, Stefano; Ciccone, Giovannino; Maisnar, Vladimír; Ruggeri, Marina; Zambello, Renato; Guglielmelli, Tommasina; Ledda, Antonio; Liberati, Anna Marina; Montefusco, Vittorio; Hajek, Roman; Boccadoro, Mario; Palumbo, Antonio


    Lenalidomide-dexamethasone improved outcome in newly diagnosed elderly multiple myeloma patients. We randomly assigned 662 patients who were age ≥65 years or transplantation-ineligible to receive induction with melphalan-prednisone-lenalidomide (MPR) or cyclophosphamide-prednisone-lenalidomide (CPR) or lenalidomide plus low-dose dexamethasone (Rd). The primary end point was progression-free survival (PFS) in triplet (MPR and CPR) vs doublet (Rd) lenalidomide-containing regimens. After a median follow-up of 39 months, the median PFS was 22 months for the triplet combinations and 21 months for the doublet (P = .284). The median overall survival (OS) was not reached in either arms, and the 4-year OS was 67% for the triplet and 58% for the doublet arms (P = .709). By considering the 3 treatment arms separately, no difference in outcome was detected among MPR, CPR, and Rd. The most common grade ≥3 toxicity was neutropenia: 64% in MPR, 29% in CPR, and 25% in Rd patients (P < .0001). Grade ≥3 nonhematologic toxicities were similar among arms and were mainly infections (6.5% to 11%), constitutional (3.5% to 9.5%), and cardiac (4.5% to 6%), with no difference among the arms. In conclusion, in the overall population, the alkylator-containing triplets MPR and CPR were not superior to the alkylator-free doublet Rd, which was associated with lower toxicity. This study was registered at as #NCT01093196.

  13. UGC 3672: An unusual merging triplet of gas-rich galaxies in the Lynx-Cancer void

    CERN Document Server

    Chengalur, Jayaram N; Egorova, E S


    We present HI 21cm and optical observations of UGC 3672 which is located near the centre of the nearby Lynx-Cancer void. We find that UGC 3672 consists of an approximately linearly aligned triplet of gas rich dwarfs with large scale velocity continuity along the triplet axis. The faintest component of the triplet is extremely gas-rich (MHI/LB ~ 17) and also extremely metal deficient (12+log(O/H) ~ 7.0). The metallicity of this dwarf is close to the 'floor' observed in star forming galaxies. Low resolution HI images show that the galaxy triplet is located inside a common HI envelope, with fairly regular, disk like kinematics. At high angular resolution however, the gas is found to be confined to several filamentary tidal tails and bridges. The linear alignment of the galaxies, along with the velocity continuity that we observe, is consistent with the galaxies lying along a filament. We argue that the location of this highly unusual system in an extremely low density environment is not a coincidence, but is a c...

  14. Singlet and Triplet Excitation Management in a Bichromophoric Near-Infrared-Phosphorescent BODIPY-Benzoporphyrin Platinum Complex

    KAUST Repository

    Whited, Matthew T.


    Multichromophoric arrays provide one strategy for assembling molecules with intense absorptions across the visible spectrum but are generally focused on systems that efficiently produce and manipulate singlet excitations and therefore are burdened by the restrictions of (a) unidirectional energy transfer and (b) limited tunability of the lowest molecular excited state. In contrast, we present here a multichromophoric array based on four boron dipyrrins (BODIPY) bound to a platinum benzoporphyrin scaffold that exhibits intense panchromatic absorption and efficiently generates triplets. The spectral complementarity of the BODIPY and porphryin units allows the direct observation of fast bidirectional singlet and triplet energy transfer processes (k ST(1BDP→1Por) = 7.8×1011 s-1, kTT(3Por→3BDP) = 1.0×1010 s-1, kTT(3BDP→ 3Por) = 1.6×1010 s-1), leading to a long-lived equilibrated [3BDP][Por]=[BDP][3Por] state. This equilibrated state contains approximately isoenergetic porphyrin and BODIPY triplets and exhibits efficient near-infrared phosphorescence (λem = 772 nm, φ = 0.26). Taken together, these studies show that appropriately designed triplet-utilizing arrays may overcome fundamental limitations typically associated with core-shell chromophores by tunable redistribution of energy from the core back onto the antennae. © 2010 American Chemical Society.

  15. The Electronic Investigation of Singlet and Triplet States of Oxyhemoglobin by Hartree-Fock Procedure and Associated Hyperfine Interaction. (United States)

    Dubey, Archana; Badu, S. R.; Scheicher, R. H.; Sahoo, N.; Pink, R. H.; Schulte, A.; Saha, H. P.; Chow, Lee; Nagamine, K.; Das, T. P.


    The observation of paramagnetic susceptibility [1] in Oxy-Hb from measurements over a broad temperature range has stimulated interest in the occurrence of a low-lying excited triplet state close to the ground singlet state of Oxy-Hb. An earlier theoretical investigation [2] has shown the existence of such a triplet state providing support to the interpretation of the susceptibility data [1]. Support for the low-lying excited triplet state has been augmented recently [3] from microscopic relaxation rate measurements for muon attached to the heme group of Oxy-Hb. We are studying by first principles Hartree-Fock procedure the energies and the electronic wave functions of the ground and triplet states and the quantitative theoretical prediction of muon magnetic hyperfine interaction in room temperature μSR measurements on Oxy-Hb. Results will be presented for hyperfine interactions of muon and other nuclei in Oxy-Hb [1] M.Cerdonio etal. Proc. Nat. Acad. Sci USA 75, 4916(1978). [2] Zalek S. Herman and Gilda H Loew JACS 102, 1815(1980).[ 3] K. Nagamine etal Proc. Jpn. Acad.Ser.B 83,120(2007).

  16. Triplet repeat sequences in human DNA can be detected by hybridization to a synthetic (5'-CGG-3')17 oligodeoxyribonucleotide

    DEFF Research Database (Denmark)

    Behn-Krappa, A; Mollenhauer, J; Doerfler, W


    The seemingly autonomous amplification of naturally occurring triplet repeat sequences in the human genome has been implicated in the causation of human genetic disease, such as the fragile X (Martin-Bell) syndrome, myotonic dystrophy (Curshmann-Steinert), spinal and bulbar muscular atrophy...

  17. Spin-Free CC2 Implementation of Induced Transitions between Singlet Ground and Triplet Excited States. (United States)

    Helmich-Paris, Benjamin; Hättig, Christof; van Wüllen, Christoph


    In most organic molecules, phosphorescence has its origin in transitions from triplet exited states to the singlet ground state, which are spin-forbidden in nonrelativistic quantum mechanics. A sufficiently accurate description of phosphorescence lifetimes for molecules that contain only light elements can be achieved by treating the spin-orbit coupling (SOC) with perturbation theory (PT). We present an efficient implementation of this approach for the approximate coupled cluster singles and doubles model CC2 in combination with the resolution-of-the-identity approximation for the electron repulsion integrals. The induced oscillator strengths and phosphorescence lifetimes from SOC-PT are computed within the response theory framework. In contrast to previous work, we employ an explicitly spin-coupled basis for singlet and triplet operators. Thereby, a spin-orbital treatment can be entirely avoided for closed-shell molecules. For compounds containing only light elements, the phosphorescence lifetimes obtained with SOC-PT-CC2 are in good agreement with those of exact two-component (X2C) CC2, whereas the calculations are roughly 12 times faster than with X2C. Phosphorescence lifetimes computed for two thioketones with the SOC-PT-CC2 approach agree very well with reference results from experiment and are similar to those obtained with multireference spin-orbit configuration interaction and with X2C-CC2. An application to phosphorescent emitters for metal-free organic light-emitting diodes (OLEDs) with almost 60 atoms and more than 1800 basis functions demonstrates how the approach extends the applicability of coupled cluster methods for studying phosphorescence. The results indicate that other decay channels like vibrational relaxation may become important in such systems if lifetimes are large.

  18. Tsallis q-triplet and Stock Market Indices: The cases of S & P 500 and TVIX

    Directory of Open Access Journals (Sweden)

    A. C. Iliopoulos


    Full Text Available In this study we present results of the evaluation of q − triplet of Tsallis non-extensive statistics concerning two time stock market time series, Standart & Poor’s 500 (S & P 500 and TVIX. The analysis of the results, support the hypothesis in which economic dynamics from physical point of view correspond to far from equilibrium spatial distributed non-linear dynamics. In particular, the analysis of the stock market time series revealed underlying complex dynamics, indicating clearly that the statistics of the dynamics in the multifractal phase space can be described by Tsallis distribution functions of power law and heavy tails forms. The non-extensive character of the underlying dynamics is related to the existence of long range interactions in space and time, as well as the interaction in many scales. In addition, the detailed analysis of S & P index unraveled the existence of non-equilibrium phase transitions depicted clearly in the variations of Tsallis q-triplet values. These phase transitions are connected with non-equilibrium stationary states of economical dynamics derived from processes of strong self organization which correspond to local maxima of Tsallis entropy, while the changes in the control parameters can induce new phase transitions and shifts to new metaequilibrium steady states of maximizing Tsallis entropy. These phase transitions lead to changes in Tsallis qtriplet values which correspond to multi-fractal changes in the formation of the phase state and an alteration in the phenomenology of the economical system. Finally, these characteristics also indicate the existence of fractional dynamics in the phase space which can be described through fractional Fokker-Planck equations and anomalous diffusion equations. The solutions of these equations are fractional spatiotemporal functions and non-Gaussian distributions functions which fall into the category of Levy distributions and Tsallis distributions.

  19. UV-Visible Spectroscopy Detection of Iron(III) Ion on Modified Gold Nanoparticles With a Hydroxamic Acid (United States)

    Karami, C.; Alizadeh, A.; Taher, M. A.; Hamidi, Z.; Bahrami, B.


    The present work describes the preparation of gold nanoparticles (AuNPs) functionalized with hydroxamic acid and the use of them in UV-visible spectroscopy detection of iron(III) ions. The prepared AuNPs were thoroughly characterized by using UV-visible spectroscopy, TEM, and 1H NMR techniques. The newly synthesized hydroxamic acid-AuNPs are brown in color due to the intense surface plasmon absorption band centered at 527 nm. In the presence of Fe(III), the surface plasmon absorption band is centered at 540 nm. However, the sensitivity of hydroxamic acid-AuNPs towards other metal ions such as Mg(II), Ca(II), Ag(I), Cu(II), Mn(II), Cr(II), Ni(II), Co(II),Fe(II), Hg(II), and Pb(II) can be negligible. This highly selective sensor allows a direct quantitative assay of Fe(III) with a UVvisible spectroscopy detection limited to 45.8 nM.

  20. Photochemical transformation of benzotriazole, relevant to sunlit surface waters: Assessing the possible role of triplet-sensitised processes

    Energy Technology Data Exchange (ETDEWEB)

    Bianco, Angelica [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); Fabbri, Debora; Minella, Marco [Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Turin (Italy); Brigante, Marcello, E-mail: [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, BP 80026, F-63177 Aubière (France); Mailhot, Gilles [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, BP 80026, F-63177 Aubière (France); Maurino, Valter; Minero, Claudio [Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Turin (Italy); Vione, Davide, E-mail: [Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Turin (Italy); Università degli Studi di Torino, Centro Interdipartimentale NatRisk, Via L. Da Vinci 44, 10095 Grugliasco (Italy)


    The corrosion inhibitor 1H-benzotriazole (pK{sub a} = 8.4) can exist in two different forms in natural waters, and photochemical transformation is a potentially significant attenuation pathway for both of them. Depending on conditions, the modelled half-life times range from some days/weeks to several months. In sunlit water bodies, the acidic (neutral) form would undergo direct photolysis (accounting for up to 7% of total phototransformation) and, most notably, reaction with the hydroxyl radicals ({sup ·}OH) and the triplet states of chromophoric dissolved organic matter ({sup 3}CDOM*). The basic (anionic) form would undergo significant transformation with {sup ·}OH and {sup 3}CDOM*. The {sup ·}OH reactions would be more important at low dissolved organic carbon (DOC) and the {sup 3}CDOM* processes at high DOC. In the presence of highly reactive triplet-state model compounds, the two benzotriazole forms react with similar rate constants. In this case, they would show comparable half-life times in surface-water environments. With less reactive triplet states, the rate constant of the anionic form can be a couple of orders of magnitude higher than that of the neutral one. Under these circumstances, the neutral form could be considerably more photostable than the anionic one at high DOC. Therefore, depending on {sup 3}CDOM* reactivity, the solution pH may or may not play an important role in the photoattenuation kinetics of 1H-benzotriazole in sunlit natural waters, especially at high DOC. Both forms of benzotriazole yield hydroxyderivatives as their main transformation intermediates under all the relevant photochemical reaction pathways. These intermediates could be formed via {sup ·}OH-induced hydroxylation, or upon electron abstraction followed by reaction with water. Differently from UVC irradiation data reported in previous studies, the concentration of aniline upon excitation of 1H-benzotriazole under environmentally significant UV wavelengths was always

  1. Astronomical Spectroscopy

    CERN Document Server

    Massey, Philip


    Spectroscopy is one of the most important tools that an astronomer has for studying the universe. This chapter begins by discussing the basics, including the different types of optical spectrographs, with extension to the ultraviolet and the near-infrared. Emphasis is given to the fundamentals of how spectrographs are used, and the trade-offs involved in designing an observational experiment. It then covers observing and reduction techniques, noting that some of the standard practices of flat-fielding often actually degrade the quality of the data rather than improve it. Although the focus is on point sources, spatially resolved spectroscopy of extended sources is also briefly discussed. Discussion of differential extinction, the impact of crowding, multi-object techniques, optimal extractions, flat-fielding considerations, and determining radial velocities and velocity dispersions provide the spectroscopist with the fundamentals needed to obtain the best data. Finally the chapter combines the previous materi...

  2. Grain Spectroscopy (United States)

    Allamandola, L. J.


    Our fundamental knowledge of interstellar grain composition has grown substantially during the past two decades thanks to significant advances in two areas: astronomical infrared spectroscopy and laboratory astrophysics. The opening of the mid-infrared, the spectral range from 4000-400 cm(sup -1) (2.5-25 microns), to spectroscopic study has been critical to this progress because spectroscopy in this region reveals more about a materials molecular composition and structure than any other physical property. Infrared spectra which are diagnostic of interstellar grain composition fall into two categories: absorption spectra of the dense and diffuse interstellar media, and emission spectra from UV-Vis rich dusty regions. The former will be presented in some detail, with the latter only very briefly mentioned. This paper summarized what we have learned from these spectra and presents 'doorway' references into the literature. Detailed reviews of many aspects of interstellar dust are given.

  3. A model for triplet mutation formation based on error-prone translesional DNA synthesis opposite UV photolesions. (United States)

    Ikehata, Hironobu; Ono, Tetsuya; Tanaka, Kiyoji; Todo, Takeshi


    A triplet mutation is defined as multiple base substitutions or frameshifts within a three-nucleotide sequence which includes a dipyrimidine sequence. Triplet mutations have recently been identified as a new type of UV-specific mutation, although the mechanism of their formation is unknown. A total of 163 triplet mutations were identified through an extensive search of previously published data on UV-induced mutations, including mutations from skin, skin cancer, and cultured mammalian cells. Seven common patterns of sequence changes were found: Type I, NTC-->TTT; Type IIa, NCC-->PyTT or PyCT (Py, pyrimidine); Type IIb, TCC-->PuTT or PuCT (Pu, purine); Type III, NCC-->NAT or NTA; Type IV, NTT-->AAT; Type Va, NCT-->NTX; and Type Vb, PuCT-->XTT (N and X, independent anonymous bases). Furthermore, it is suggested that the type of UV lesion responsible for each of these triplet mutation classes are (a) pyrimidine(6-4)pyrimidone photoproducts for Types I, IIb, III, IV and Vb, (b) cyclobutane pyrimidine dimers for Type Va, and (c) Dewar valence isomers for Types IIa and IIb. These estimations are based primarily on results from previous studies using photolyases specific for each type of UV lesion. A model is proposed to explain the formation of each type of triplet mutation, based on error-prone translesional DNA synthesis opposite UV-specific photolesions. The model is largely consistent with the 'A-rule', and predicts error-prone insertions not only opposite photolesions but also opposite the undamaged template base one-nucleotide downstream from the lesions.

  4. Least-squares self-coherency analysis of superconducting gravimeter records in search for the Slichter triplet (United States)

    Pagiatakis, Spiros D.; Yin, Hui; El-Gelil, Mahmoud Abd


    We develop a new approach for the spectral analysis of the superconducting gravimeter data to search for the spheroidal oscillation 1S1 of the Earth solid inner core. The new method, which we call least- squares ( LS) self- coherency analysis, is based on the product of the least-squares spectra of segments of the time series under consideration. The statistical foundation of this method is presented in the new least- squares product spectrum theorem that establishes rigorously confidence levels for detecting significant peaks. We apply this approach along with a number of other innovative ideas to a 6-year long gravity series collected at the Canadian Superconducting Gravimeter Installation (CSGI) in Cantley, Canada, by splitting it into 72 statistically independent monthly records. Each monthly record is analysed spectrally and all monthly LS spectra are multiplied to construct the self- coherency spectrum of the 6-year gravity series. The self-coherency spectrum is then used to detect significant peaks in the band 3-7 h at various significant levels with the aim to identify a triplet of periods associated with the rotational/ellipsoidal splitting of 1S1 (Slichter triplet). From all the Slichter periods predicted by various researchers so far, Smylie's triplet appears to be the most supported one, albeit very weakly, both, before and after the atmospheric pressure effect is removed from the series. Using the viscous splitting law [Smylie, D.E., 1992. The inner core translational triplet and the density near Earth's center. Science 255, 1678-1682] as guide, we can also see one interesting and statistically significant triplet with periods A = {4.261 h, 4.516 h, 4.872 h}, which changes slightly to A' = {4.269 h, 4.516 h, 4.889 h} after the atmospheric pressure correction is applied to the gravity series.

  5. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang


    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., frequency doubling in external cavities, reliable cw-parametric oscillators, tunable narrow-band UV sources, more sensitive detection techniques, tunable femtosecond and sub-femtosecond lasers (X-ray region and the attosecond range), control of atomic and molecular excitations, frequency combs able to synchronize independent femtosecond lasers, coherent matter waves, and still more applications in chemical analysis, medical diagnostics, and engineering.

  6. Interaction of inhibition and triplets of excitatory spikes modulates the NMDA-R-mediated synaptic plasticity in a computational model of spike timing-dependent plasticity. (United States)

    Cutsuridis, Vassilis


    Spike timing-dependent plasticity (STDP) experiments have shown that a synapse is strengthened when a presynaptic spike precedes a postsynaptic one and depressed vice versa. The canonical form of STDP has been shown to have an asymmetric shape with the peak long-term potentiation at +6 ms and the peak long-term depression at -5 ms. Experiments in hippocampal cultures with more complex stimuli such as triplets (one presynaptic spike combined with two postsynaptic spikes or one postsynaptic spike with two presynaptic spikes) have shown that pre-post-pre spike triplets result in no change in synaptic strength, whereas post-pre-post spike triplets lead to significant potentiation. The sign and magnitude of STDP have also been experimentally hypothesized to be modulated by inhibition. Recently, a computational study showed that the asymmetrical form of STDP in the CA1 pyramidal cell dendrite when two spikes interact switches to a symmetrical one in the presence of inhibition under certain conditions. In the present study, I investigate computationally how inhibition modulates STDP in the CA1 pyramidal neuron dendrite when it is driven by triplets. The model uses calcium as the postsynaptic signaling agent for STDP and is shown to be consistent with the experimental triplet observations in the absence of inhibition: simulated pre-post-pre spike triplets result in no change in synaptic strength, whereas simulated post-pre-post spike triplets lead to significant potentiation. When inhibition is bounded by the onset and offset of the triplet stimulation, then the strength of the synapse is decreased as the strength of inhibition increases. When inhibition arrives either few milliseconds before or at the onset of the last spike in the pre-post-pre triplet stimulation, then the synapse is potentiated. Variability in the frequency of inhibition (50 vs. 100 Hz) produces no change in synaptic strength. Finally, a 5% variation in model's calcium parameters (calcium thresholds

  7. Focal point analysis of the singlet-triplet energy gap of octacene and larger acenes. (United States)

    Hajgató, Balázs; Huzak, Matija; Deleuze, Michael S


    A benchmark theoretical study of the electronic ground state and of the vertical and adiabatic singlet-triplet (ST) excitation energies of n-acenes (C(4n+2)H(2n+4)) ranging from octacene (n = 8) to undecacene (n = 11) is presented. The T1 diagnostics of coupled cluster theory and further energy-based criteria demonstrate that all investigated systems exhibit predominantly a (1)A(g) singlet closed-shell electronic ground state. Singlet-triplet (S(0)-T(1)) energy gaps can therefore be very accurately determined by applying the principle of a focal point analysis (FPA) onto the results of a series of single-point and symmetry-restricted calculations employing correlation consistent cc-pVXZ basis sets (X = D, T, Q, 5) and single-reference methods [HF, MP2, MP3, MP4SDQ, CCSD, and CCSD(T)] of improving quality. According to our best estimates, which amount to a dual extrapolation of energy differences to the level of coupled cluster theory including single, double, and perturbative estimates of connected triple excitations [CCSD(T)] in the limit of an asymptotically complete basis set (cc-pV∞Z), the S(0)-T(1) vertical (adiabatic) excitation energies of these compounds amount to 13.40 (8.21), 10.72 (6.05), 8.05 (3.67), and 7.10 (2.58) kcal/mol, respectively. In line with the absence of Peierls distortions (bond length alternations), extrapolations of results obtained at this level for benzene (n = 1) and all studied n-acenes so far (n = 2-11) indicate a vanishing S(0)-T(1) energy gap, in the limit of an infinitely large polyacene, within an uncertainty of 1.5 kcal/mol (0.06 eV). Lacking experimental values for the S(0)-T(1) energy gaps of n-acenes larger than hexacene, comparison is made with recent optical and electrochemical determinations of the HOMO-LUMO band gap. Further issues such as scalar relativistic, core correlation, and diagonal Born-Oppenheimer corrections (DBOCs) are tentatively examined.

  8. Strongly frustrated triangular spin lattice emerging from triplet dimer formation in honeycomb Li2IrO3 (United States)

    Nishimoto, Satoshi; Katukuri, Vamshi M.; Yushankhai, Viktor; Stoll, Hermann; Rößler, Ulrich K.; Hozoi, Liviu; Rousochatzakis, Ioannis; van den Brink, Jeroen


    Iridium oxides with a honeycomb lattice have been identified as platforms for the much anticipated Kitaev topological spin liquid: the spin-orbit entangled states of Ir4+ in principle generate precisely the required type of anisotropic exchange. However, other magnetic couplings can drive the system away from the spin-liquid phase. With this in mind, here we disentangle the different magnetic interactions in Li2IrO3, a honeycomb iridate with two crystallographically inequivalent sets of adjacent Ir sites. Our ab initio many-body calculations show that, while both Heisenberg and Kitaev nearest-neighbour couplings are present, on one set of Ir-Ir bonds the former dominates, resulting in the formation of spin-triplet dimers. The triplet dimers frame a strongly frustrated triangular lattice and by exact cluster diagonalization we show that they remain protected in a wide region of the phase diagram.

  9. High-Yield Excited Triplet States in Pentacene Self-Assembled Monolayers on Gold Nanoparticles through Singlet Exciton Fission. (United States)

    Kato, Daiki; Sakai, Hayato; Tkachenko, Nikolai V; Hasobe, Taku


    One of the major drawbacks of organic-dye-modified self-assembled monolayers on metal nanoparticles when employed for efficient use of light energy is the fact that singlet excited states on dye molecules can be easily deactivated by means of energy transfer to the metal surface. In this study, a series of 6,13-bis(triisopropylsilylethynyl)pentacene-alkanethiolate monolayer protected gold nanoparticles with different particle sizes and alkane chain lengths were successfully synthesized and were employed for the efficient generation of excited triplet states of the pentacene derivatives by singlet fission. Time-resolved transient absorption measurements revealed the formation of excited triplet states in high yield (172±26 %) by suppressing energy transfer to the gold surface.

  10. Synthesis of novel triplets with a 1,3,5-trioxazatriquinane skeleton and their pharmacologies for opioid receptors. (United States)

    Nagase, Hiroshi; Kutsumura, Noriki


    We designed and synthesized novel triplet molecules with 1,3,5-trioxazatriquinane skeletons. One class comprises double-capped triplets with a morphinan skeleton; the other class comprises simple phenol derivatives with phenethylamine moieties. One compound with m-phenolic hydroxyl group, called SYK-146, is a highly selective, potent agonist for the κ receptor, with activity nearly equivalent to that of U-50488H. The o-phenolic isomer of SYK-146, called SYK-524, showed potent but non-selective agonistic activity for the opioid receptors. We also added several simple phenol derivatives to a library of compounds that target opioid receptors, and they showed high hit rates for the receptor. This library might also be expected to show high hit rates for other receptors.

  11. Zero-field splitting of the first excited triplet state in biradicals estimated from magnetic effects on the fluorescence decays

    Energy Technology Data Exchange (ETDEWEB)

    LeJeune, V.; Despres, A.; Migirdicyan, E. (Universite Paris-Sud, Orsay (France))


    The fluorescence decay of matrix-isolated m-xylylene biradicals is nonexponential and attributed to the emission from different sublevels of the first excited triplet state. In the presence of a magnetic field, the lifetime of the slow decay component decreases. Its dependence as a function of a weak magnetic field can be calculated for different values of the zero-field splitting parameter D. The best fitting value is {vert bar}D{vert bar} = 0.04 {plus minus} 0.01 cm{sup {minus}1}. This D value is found to be significantly larger in the first excited triplet state than in the ground state of the m-xylylene biradicals.

  12. Isothermal density derivative of S(k) and the triplet correlation function: an experimental study in liquid Kr (United States)

    Fontana, Raffaella; Magli, Renato


    Recent accurate measurements performed on liquid Kr have been used to test some of the models proposed in the literature for the triplet correlation function g 3( r, s). It turns out that neither the superposition approximation suggested by Kirkwood (J.P. Hansen and I.R. McDonald, Theory of simple liquids, Academic Press, London, 1986), nor a modification of it which partially takes into account linear density effects (H. Fredrikze, Ph.D. Thesis, Delft, 1985) are able to satisfactorily reproduce the experimental isothermal derivatives of the structure factor. Also the uniform fluid model (P.A. Egelstaff, D.I. Page and C.R.T. Heard, J. Phys. C, 4 (1971) 1453), gives a poor representation especially at lower densities. It is concluded that, in order to correctly describe triplet correlation effects, a full account of the irreducible contributions to g 3( r, s) is necessary.


    Directory of Open Access Journals (Sweden)

    M. Ghaffarnejad


    Full Text Available Acute fatty liver of pregnancy (AFLP is a rare entity and a potentially fatal disorder. It is reported to be more common in multiple than singleton pregnancies. Sometimes it coincides with preeclampsia but the exact etiology is not yet understood. A 31-year-old G2 P1 patient admitted at 33 weeks of pregnancy with signs and symptoms of jaundice, gastroenteritis, hypertension, malaise, urinary incontinence and preterm contractions. She had history of idiopathic hypothalamic amenorrhea and by a recent trial with gonadotropins, she had got triplet gestation. After admission her general condition deteriorated. She underwent Cesarean section at once and all fetuses survived. She had severe postpartum hemorrhage. The results of laboratory tests indicated coagulopathy and liver function abnormalities. The AFLP was diagnosed on the third day of hospital stay. She was discharged one week later. Again she returned with complaint of severe sustained headache. Computed tomography showed subdural hemorrhage and drainage of hematoma was performed immediately. Finally the patient recovered from all of these critical conditions. This is the first report of AFLP in a patient with history of idiopathic hypothalamic amenorrhea. AFLP should be suspected in every pregnant patient with preeclampsia and gastroenteritis symptoms in the third trimester of pregnancy.

  14. Tsallis Distributions and the q-Triplet of the Magnetic Field in the Heliosheath (United States)

    Burlaga, L. F.


    The Tsallis distribution (which is proportional to the q-exponential function and is related to the κ-distribution) was derived from an entropy function, inspired by multifractals, which gives a generalization of Boltzmann-Gibbs statistical mechanics. A Tsallis distribution describes the distribution of increments of daily averages of the magnetic field strength B observed by Voyager 2 (V2) in the heliosheath during 2010 in association with exceptionally low solar activity. A parameter q derived from this distribution is qstat = 1.75. The correlation function of B(t) is a power law on scales from 1 to 16 days, and from the exponent one obtains the parameter qrel = 3.9. The fluctuations of B are described by a multifractal spectrum f(α) on scales from 1 to 8 days, from which one obtains qsen = 1.75. The "q-triplet" (qsen, qrel, qstat) defines basic observable properties of an open, driven system in a meta-equilibrium state, which strongly constrains physical models of the system. The distribution of B is Gaussian, probably related to the unipolar region in which V2 was located. A 1/f spectrum of B was observed on scales from 1 to 100 days. The Tsallis distribution also describes the "turbulence" observed on very small scales, from 48 sec to several hours, observed by V2 behind the termination shock from day 245 - 301, 2007.

  15. Photophysics of phenalenone: quantum-mechanical investigation of singlet-triplet intersystem crossing. (United States)

    Daza, Martha C; Doerr, Markus; Salzmann, Susanne; Marian, Christel M; Thiel, Walter


    We have examined the electronic and molecular structure of 1H-phenalen-1-one (phenalenone) in the electronic ground state and in the lowest excited states, as well as intersystem crossing. The electronic structure was calculated using a combination of density functional theory and multi-reference configuration interaction. Intersystem crossing rates were determined using Fermi's golden rule and taking direct and vibronic spin-orbit coupling into account. The required spin-orbit matrix elements were obtained applying a non-empirical spin-orbit mean-field approximation. Our calculated electronic energies are in good agreement with experimental data. We find the lowest excited singlet states to be of the npi* (S1) and pipi* (S2) type. Energetically accessible from S1 are two triplet states of the pipi* (T1) and npi* (T2) type, the latter being nearly degenerate to S1. This ordering of states is retained when the molecular structure in the electronically excited states is relaxed. We expect very efficient intersystem crossing between S1 and T1. Our calculated intersystem crossing rate is approximately 2 x 10(10) s(-1), which is in excellent agreement with the experimental value of 3.45 x 10(10) s(-1). Our estimated phosphorescence and fluorescence rates are many orders of magnitude smaller. Our results are in agreement with the experimentally observed behavior of phenalenone, including the high efficiency of 1O2 production.

  16. Photoexcited triplet state provides a quantitative measure of intercalating drug-DNA binding energies (United States)

    Maki, August H.; Alfredson, T. V.; Waring, M. J.


    A linear correlation between spectroscopic and thermodynamic properties of systems is rarely encountered. In triplet state ODMR studies of various DNA complexes of echinomycin, a quinoxaline-containing cyclic depsipeptide bis-intercalating antibiotic, and its biosynthesized quinoline analogs, such correlations are observed. The zero field splitting D-parameter of the intercalated quinoxaline or quinoline residue varies linearly with the free energy of drug-DNA complexing. From previous work, the DNA sequence specificity of echinomycin analogs is known to be influenced by the identity of the intercalating residue (e.g., quinoxaline vs. quinoline). The present results strongly suggest that the DNA sequence-specificity of these drugs is controlled largely by the intercalated residue, and that the energetics of the peptide- DNA interaction, although considerable, are relatively sequence independent. These conclusions run counter to the generally accepted idea that DNA recognition by sequence- seeking proteins is controlled by specific hydrogen bonding interactions. The high degree of N-methylation of the echinomycin peptide portion severely restricts these interactions, however. A simple theoretical model is presented to support the experimentally observed linear correlation between (Delta) D and (Delta) G.

  17. Spin-triplet electron transport in hybrid superconductor heterostructures with a composite ferromagnetic interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Sheyerman, A. E., E-mail:; Constantinian, K. Y.; Ovsyannikov, G. A.; Kislinskii, Yu. V.; Shadrin, A. V. [Russian Academy of Sciences, Kotelnikov Institute of Radio Engineering and Electronics (Russian Federation); Kalabukhov, A. V. [Chalmers University of Technology (Sweden); Khaydukov, Yu. N. [Max-Planck Institute for Solid State Research (Germany)


    Hybrid YBa{sub 2}Cu{sub 3}O{sub 7−x}/SrRuO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/Au-Nb superconductor mesastructures with a composite manganite-ruthenate ferromagnetic interlayer are studied using electrophysical, magnetic, and microwave methods. The supercurrent in the mesastructure is observed when the interlayer thickness is much larger than the coherence length of ferromagnetic materials. The peak on the dependence of the critical current density on the interlayer material thickness corresponds to the coherence length, which is in qualitative agreement with theoretical predictions for a system with spit-triplet superconducting correlations. The magnetic-field dependence of the critical current is determined by penetration of magnetic flux quanta and by the magnetic domain structure, as well as by the field dependence of disorientation of the magnetization vectors of the layers in the composite magnetic interlayer. It is found that the supercurrent exists in magnetic fields two orders of magnitude stronger than the field corresponding to entry of a magnetic flux quantum into the mesastructure. The current-phase relation (CPR) of the supercurrent of mesastructures is investigated upon a change in the magnetic field from zero to 30 Oe; the ratio of the second CPR harmonic to the first, determined from the dependence of the Shapiro steps on the microwave radiation amplitude, does not exceed 50%.

  18. Resolution limit of probe-forming systems with magnetic quadrupole lens triplets and quadruplets

    CERN Document Server

    Ponomarev, A G; Miroshnichenko, V I; Storizhko, V E; Sulkio-Cleff, B


    Over the past decade, in MeV ion beam microanalysis efforts to achieve a spatial resolution better than 0.1 mu m with a beam current of approx 100 pA have been connected with microprobes of new generation where the probe is formed by means of separated magnetic quadrupole lens structures . However, as was pointed out in , no dramatic improvements in spatial resolution have been produced so far. For better understanding of the situation the authors carried out theoretical studies of multiparameter sets of probe-forming systems based on separated triplets and quadruplets of magnetic quadrupole lenses. Comparisons were made between the highest current values attained at different systems for a given beam spot size. The maximum parasitic sextupole and octupole field components were found whose contributions to spot broadening are tolerable. It is shown that the use of modern electrostatic accelerators and precision magnetic quadrupole lenses makes it possible to eliminate the effect of chromatic aberrations and s...

  19. Ordinary and triplet superconducting spin valve effect in Fe/Pb based systems

    Energy Technology Data Exchange (ETDEWEB)

    Leksin, Pavel; Schumann, Joachim; Krupskaya, Yulia; Kataev, Vladislav; Hess, Christian; Schmidt, Oliver; Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany); Garifyanov, Nadir; Garifullin, Ilgiz [Zavoisky Physical-Technical Institute of RAS, Kazan (Russian Federation); Fominov, Yakov [L. D. Landau Institute for Theoretical Physics of RAS, Moscow (Russian Federation)


    We report on experimental evidence for the occurrence of the long range triplet correlations (LRTC) of the superconducting (SC) condensate in the spin-valve heterostructures CoO{sub x}/Fe1/Cu/Fe2/Pb. The LRTC generation in this layer sequence is accompanied by a T{sub c} suppression near the orthogonal mutual orientation of the Fe1 and Fe2 layers' magnetization. This T{sub c} drop reaches its maximum of 60mK at the Fe2 layer thickness d{sub Fe2} = 0.6 nm and falls down when d{sub Fe2} is increased. The modification of the Fe/Pb interface by using a thin Cu layer between Fe and Pb layers reduces the SC transition width without preventing the interaction between Pb and Fe2 layers. The dependence of the SSVE magnitude on Fe1 layer thickness d{sub Fe1} reveals maximum of the effect when d{sub Fe1} and d{sub Fe2} are equal and the d{sub Fe2} value is minimal. Using the optimal d{sub Fe1}, d{sub Fe2} and the intermediate Cu layer we realized almost full switching from normal to SC state due to SSVE.

  20. Observations and theoretical analysis of highly excited singlet and triplet states of cadmium (United States)

    Vidolova-Angelova, E.; Baharis, C.; Roupakas, G.; Kompitsas, M.


    We have recorded the 0953-4075/29/12/010/img7 - 50) bound Rydberg spectrum of cadmium. We have fully resolved the multiplet up to n = 19 and partially up to n = 24. Furthermore, we have observed the odd singlet and triplet 5sn f Rydberg series for n = 10 - 22 and n = 4 - 21, respectively. We have applied two- and three-step laser schemes to excite Cd vapour in a heat pipe-like oven which was operated as a thermionic diode for detection. Theoretical calculations were performed for the energies of the 5sn p and 5sn f series using perturbation theory with a zero-order model approximation. There is a good agreement between theoretical and experimental results for the 5sn p series, the deviation decreasing with n and being 1 - 2 0953-4075/29/12/010/img8 for n = 50. The agreement for the 5sn f is satisfactory. From the quantum defect of the 5sn f series we approximate a value of the effective dipole polarizability of the 0953-4075/29/12/010/img9 ion of 0953-4075/29/12/010/img10 in units of the Bohr radius.

  1. Walking Down the Chalcogenic Group of the Periodic Table: From Singlet to Triplet Organic Emitters. (United States)

    Kremer, Adrian; Aurisicchio, Claudia; De Leo, Federica; Ventura, Barbara; Wouters, Johan; Armaroli, Nicola; Barbieri, Andrea; Bonifazi, Davide


    The synthesis, X-ray crystal structures, ground- and excited-state UV/Vis absorption spectra, and luminescence properties of chalcogen-doped organic emitters equipped on both extremities with benzoxa-, benzothia-, benzoselena- and benzotellurazole (1X and 2X ) moieties have been reported for the first time. The insertion of the four different chalcogen atoms within the same molecular skeleton enables the investigation of only the chalcogenic effect on the organisation and photophysical properties of the material. Detailed crystal-structure analyses provide evidence of similar packing for 2O -2Se , in which the benzoazoles are engaged in π-π stacking and, for the heavier atoms, in secondary X⋅⋅⋅X and X⋅⋅⋅N bonding interactions. Detailed computational analysis shows that the arrangement is essentially governed by the interplay of van der Waals and secondary bonding interactions. Progressive quenching of the fluorescence and concomitant onset of phosphorescence features with gradually shorter lifetimes are detected as the atomic weight of the chalcogen heteroatom increases, with the tellurium-doped derivatives exhibiting only emission from the lowest triplet excited state. Notably, the phosphorescence spectra of the selenium and tellurium derivatives can be recorded even at room temperature; this is a very rare finding for fully organic emitters.

  2. Search for double charmonium decays of the P-wave spin-triplet bottomonium states

    CERN Document Server

    Shen, C P; Iijima, T


    Using a sample of 158 million $\\Upsilon(2S)$ events collected with the Belle detector, we search for the first time for double charmonium decays of the $P$-wave spin-triplet bottomonium states ($\\Upsilon(2S) \\to \\gamma \\chi_{bJ}$, $\\chi_{bJ} \\to \\jpsi \\jpsi$, $\\jpsi \\psp$, $\\psp \\psp$ for J=0, 1, and 2). No significant $\\chi_{bJ}$ signal is observed in the double charmonium mass spectra, and we obtain the following upper limits, $\\BR(\\chi_{bJ} \\to \\jpsi \\jpsi)<7.1\\times 10^{-5}$, $2.7\\times 10^{-5}$, $4.5\\times 10^{-5}$, $\\BR(\\chi_{bJ} \\to \\jpsi \\psp)<1.2\\times 10^{-4}$, $1.7\\times 10^{-5}$, $4.9\\times 10^{-5}$, $\\BR(\\chi_{bJ} \\to \\psp \\psp)<3.1\\times 10^{-5}$, $6.2\\times 10^{-5}$, $1.6\\times 10^{-5}$ for J=0, 1, and 2, respectively, at the 90% confidence level. These limits are significantly lower than the central values (with uncertainties of 50% to 70%) predicted using the light cone formalism but are consistent with calculations using the NRQCD factorization approach.

  3. On intrinsic structure of wave function of fermion triplet in external monopole field

    CERN Document Server

    Redkov, V M


    Using the Weyl-Tetrode-Fock spinor formalism, the fermion triplet in the 't Hooft-Polyakov monopole field is examined all over again. Spherical solutions corresponding to the total conserved momentum J =l + S + T are constructed. The angular dependence is expressed in terms of the Wigner's functions. The radial system of 12 equations decomposes into two sub-systems by diagonalizing some complicated inversion operator. The case of minimal j = 1/2 is considered separately. A more detailed analysis is accomplished for the case of simplest monopole field: namely, the one produced by putting the Dirac potential into the non-Abelian scheme. Now a discrete operation diagonalized contains an additional complex parameter A. The same parameter enters wave functions. This quantity can manifest itself at matrix elements. In particular, there have been analyzed the N(A)-parity selection rules: those depending on the A. As shown, the A-freedom is a consequence of the existence of additional symmetry of the relevant Hamilto...

  4. Combustion stability characteristics of the model chamber with various configurations of triplet impinging-jet injectors

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Chae Hoon [Chosun University, Gwangju (Korea, Republic of); Seol, Woo Seok [Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Shibanov, Alexander A. [Research Institute of Chemical Machine Building, Sergiev Posad (Russian Federation)


    Combustion stability characteristics in actual full-scale combustion chamber of a rocket engine are investigated by experimental tests with the model (sub-scale) chamber. The present hot-fire tests adopt the combustion chamber with three configurations of triplet impinging-jet injectors such as F-O-O-F, F-O-F, and O-F-O configurations. Combustion stability boundaries are obtained and presented by the parameters of combustion-chamber pressure and mixture (oxidizer/fuel) ratio. From the experimental tests, two instability regions are observed and the pressure oscillations have the similar patterns irrespective of injector configuration. But, the O-F-O injector configuration shows broader upper-instability region than the other configurations. To verify the instability mechanism for the lower and upper instability regions, air-purge acoustic test is conducted and the photograph of the flames is taken. As a result, it is found that the pressure oscillations in the two regions can be characterized by the first impinging point of hydraulic jets and pre-blowout combustion, respectively.

  5. Initial singlet and triplet spin state contributions to -> ppπ0 (United States)

    Thörngren Engblom, P.; Meyer, H. O.; Balewski, J. T.; Daehnick, W. W.; Doskow, J.; Haeberli, W.; Lorentz, B.; Pancella, P. V.; Pollock, R. E.; von Przewoski, B.; Rathmann, F.; Rinckel, T.; Saha, Swapan K.; Schwartz, B.; Wellinghausen, A.; Wise, T.


    The PINTEX2"fn2">2 facility at the IUCF Cooler ring, dedicated to the study of spin dependence in nucleon-nucleon interactions, has been used to measure polarization observables of the reaction -> ppπ0 at beam energies between 325 and 400 MeV. The stored, polarized proton beam had spin projections both in the longitudinal and the transverse directions with respect to the beam momentum. We report here on the measurements of the relative transverse and longitudinal spin-dependent cross sections3Defined as ΔσT(L) = [σ(⇕) + σ(⇕)] - [σ(⇈ + σ(⇊)] where the arrows denote parallel and antiparallel beam/target spin combinations, either transversely (T) or longitudinally (L) polarized.refid="fn3">3, ΔσT/σtot and ΔσL/σtot, and how from these observables the initial spin singlet and triplet cross sections are obtained. Considering angular momentum states less than or equal to one, the contribution of the Ps partial waves to the cross section can be extracted.

  6. Simultaneous Faraday filtering of the Mollow triplet sidebands with the Cs-D1 clock transition (United States)

    Portalupi, Simone Luca; Widmann, Matthias; Nawrath, Cornelius; Jetter, Michael; Michler, Peter; Wrachtrup, Jörg; Gerhardt, Ilja


    Hybrid quantum systems integrating semiconductor quantum dots (QDs) and atomic vapours become important building blocks for scalable quantum networks due to the complementary strengths of individual parts. QDs provide on-demand single-photon emission with near-unity indistinguishability comprising unprecedented brightness--while atomic vapour systems provide ultra-precise frequency standards and promise long coherence times for the storage of qubits. Spectral filtering is one of the key components for the successful link between QD photons and atoms. Here we present a tailored Faraday anomalous dispersion optical filter based on the caesium-D1 transition for interfacing it with a resonantly pumped QD. The presented Faraday filter enables a narrow-bandwidth (Δω=2π × 1 GHz) simultaneous filtering of both Mollow triplet sidebands. This result opens the way to use QDs as sources of single as well as cascaded photons in photonic quantum networks aligned to the primary frequency standard of the caesium clock transition.

  7. The Displaced Dusty ISM of NGC 3077: Tidal Stripping in the M 81 Triplet

    CERN Document Server

    Walter, Fabian; Aniano, G; Calzetti, D; Croxall, K; Dale, D A; Draine, B T; Engelbracht, C; Hinz, J; Kennicutt, R C; Wolfire, M; Armus, L; Beirao, P; Bolatto, A D; Brandl, B; Crocker, A; Galametz, M; Groves, B; Hao, C -N; Helou, G; Hunt, L; Koda, J; Krause, O; Leroy, A; Meidt, S; Murphy, E J; Rahman, N; Rix, H -W; Roussel, H; Sauvage, M; Schinnerer, E; Skibba, R; Smith, J D; Wilson, C D; Zibetti, S


    We present the detection of extended (~30 kpc^2) dust emission in the tidal \\hi\\ arm near NGC 3077 (member of the M\\,81 triplet) using SPIRE on board Herschel. Dust emission in the tidal arm is typically detected where the \\hi\\ column densities are >10^21 cm^-2. The SPIRE band ratios show that the dust in the tidal arm is significantly colder (~13 K) than in NGC 3077 itself (~31 K), consistent with the lower radiation field in the tidal arm. The total dust mass in the tidal arm is ~1.8 x 10^6 M_sun (assuming beta=2), i.e. substantially larger than the dust mass associated with NGC 3077 (~2 x 10^5 M_sun). Where dust is detected, the dust-to-gas ratio is 6+/-3 x 10^-3, consistent within the uncertainties with what is found in NGC 3077 and nearby spiral galaxies with Galactic metallicities. The faint HII regions in the tidal arm can not be responsible for the detected enriched material and are not the main source of the dust heating in the tidal arm. We conclude that the interstellar medium (atomic HI, molecules...

  8. Cryogenic Memories based on Spin-Singlet and Spin-Triplet Ferromagnetic Josephson Junctions (United States)

    Gingrich, Eric

    The last several decades have seen an explosion in the use and size of computers for scientific applications. The US Department of Energy has set an ExaScale computing goal for high performance computing that is projected to be unattainable by current CMOS computing designs. This has led to a renewed interest in superconducting computing as a means of beating these projections. One of the primary requirements of this thrust is the development of an efficient cryogenic memory. Estimates of power consumption of early Rapid Single Flux Quantum (RSFQ) memory designs are on the order of MW, far too steep for any real application. Therefore, other memory concepts are required. S/F/S Josephson Junctions, a class of device in which two superconductors (S) are separated by one or more ferromagnetic layers (F) has shown promise as a memory element. Several different systems have been proposed utilizing either the spin-singlet or spin-triplet superconducting states. This talk will discuss the concepts underpinning these devices, and the recent work done to demonstrate their feasibility. This research is supported in part by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), via U.S. Army Research Office Contract W911NF-14-C-0115.

  9. Intermolecular Singlet and Triplet Exciton Transfer Integrals from Many-Body Green's Functions Theory. (United States)

    Wehner, Jens; Baumeier, Björn


    A general approach to determine orientation and distance-dependent effective intermolecular exciton transfer integrals from many-body Green's functions theory is presented. On the basis of the GW approximation and the Bethe-Salpeter equation (BSE), a projection technique is employed to obtain the excitonic coupling by forming the expectation value of a supramolecular BSE Hamiltonian with electron-hole wave functions for excitations localized on two separated chromophores. Within this approach, accounting for the effects of coupling mediated by intermolecular charge transfer (CT) excitations is possible via perturbation theory or a reduction technique. Application to model configurations of pyrene dimers shows an accurate description of short-range exchange and long-range Coulomb interactions for the coupling of singlet and triplet excitons. Computational parameters, such as the choice of the exchange-correlation functional in the density-functional theory (DFT) calculations that underly the GW-BSE steps and the convergence with the number of included CT excitations, are scrutinized. Finally, an optimal strategy is derived for simulations of full large-scale morphologies by benchmarking various approximations using pairs of dicyanovinyl end-capped oligothiophenes (DCV5T), which are used as donor material in state-of-the-art organic solar cells.

  10. Optimization of Triplet Quadrupoles Field Quality for the LHC High Luminosity Lattice at Collision Energy

    CERN Document Server

    Nosochkov, Y; Wang, MH; Fartoukh, S; Giovannozzi, M; de Maria, R; McIntosh, E


    Beta functions at two interaction points (IP) in the high luminosity LHC upgrade lattice (HL-LHC) at collision energy will be significantly reduced compared to the nominal LHC lattice. This will result in much higher beta functions in the inner triplet (IT) quadrupoles adjacent to these IPs. The consequences are a larger beam size in these quadrupoles, higher IT chromaticity, and stronger effects of the IT field errors on dynamic aperture (DA). The IT chromaticity will be compensated using the Achromatic Telescopic Squeezing scheme [1]. The increased IT beam size will be accommodated by installing large aperture Nb3Sn superconducting quadrupoles with 150 mm coil diameter. The stronger effects of the IT field errors can be remedied by optimizing the IT field error specifications. The latter must satisfy two conditions: provide an acceptable DA and be compatible with realistically achievable field quality. Optimization of the IT field errors was performed for the LHC upgrade layout version SLHCV3.01 with IT gra...

  11. DMRG-SCF study of the singlet, triplet, and quintet states of oxo-Mn(Salen)

    CERN Document Server

    Wouters, Sebastian; Van Der Voort, Pascal; Van Speybroeck, Veronique; Van Neck, Dimitri


    We use CheMPS2, our free open-source spin-adapted implementation of the density matrix renormalization group (DMRG) [Wouters et al., Comput. Phys. Commun. 185, 1501 (2014)], to study the lowest singlet, triplet, and quintet states of the oxo-Mn(Salen) complex. We describe how an initial approximate DMRG calculation in a large active space around the Fermi level can be used to obtain a good set of starting orbitals for subsequent complete-active-space or DMRG self-consistent field (CASSCF or DMRG-SCF) calculations. This procedure mitigates the need for a localization procedure, followed by a manual selection of the active space. Per multiplicity, the same active space of 28 electrons in 22 orbitals (28e, 22o) is obtained with the 6-31G*, cc-pVDZ, and ANO-RCC-VDZP basis sets (the latter with DKH2 scalar relativistic corrections). Our calculations provide new insight into the electronic structure of the quintet.

  12. Potential energy surface of triplet N{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Varga, Zoltan; Meana-Pañeda, Rubén; Song, Guoliang; Paukku, Yuliya; Truhlar, Donald G., E-mail: [Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431 (United States)


    We present a global ground-state triplet potential energy surface for the N{sub 2}O{sub 2} system that is suitable for treating high-energy vibrational-rotational energy transfer and collision-induced dissociation. The surface is based on multi-state complete-active-space second-order perturbation theory/minimally augmented correlation-consistent polarized valence triple-zeta electronic structure calculations plus dynamically scaled external correlation. In the multireference calculations, the active space has 14 electrons in 12 orbitals. The calculations cover nine arrangements corresponding to dissociative diatom-diatom collisions of N{sub 2}, O{sub 2}, and nitric oxide (NO), the interaction of a triatomic molecule (N{sub 2}O and NO{sub 2}) with the fourth atom, and the interaction of a diatomic molecule with a single atom (i.e., the triatomic subsystems). The global ground-state potential energy surface was obtained by fitting the many-body interaction to 54 889 electronic structure data points with a fitting function that is a permutationally invariant polynomial in terms of bond-order functions of the six interatomic distances.

  13. Simultaneous Faraday filtering of the Mollow triplet sidebands with the Cs-D1 clock transition. (United States)

    Portalupi, Simone Luca; Widmann, Matthias; Nawrath, Cornelius; Jetter, Michael; Michler, Peter; Wrachtrup, Jörg; Gerhardt, Ilja


    Hybrid quantum systems integrating semiconductor quantum dots (QDs) and atomic vapours become important building blocks for scalable quantum networks due to the complementary strengths of individual parts. QDs provide on-demand single-photon emission with near-unity indistinguishability comprising unprecedented brightness-while atomic vapour systems provide ultra-precise frequency standards and promise long coherence times for the storage of qubits. Spectral filtering is one of the key components for the successful link between QD photons and atoms. Here we present a tailored Faraday anomalous dispersion optical filter based on the caesium-D1 transition for interfacing it with a resonantly pumped QD. The presented Faraday filter enables a narrow-bandwidth (Δω=2π × 1 GHz) simultaneous filtering of both Mollow triplet sidebands. This result opens the way to use QDs as sources of single as well as cascaded photons in photonic quantum networks aligned to the primary frequency standard of the caesium clock transition.

  14. Non-LTE inversions of the Mg II h&k and UV triplet lines

    CERN Document Server

    Rodríguez, Jaime de la Cruz; Ramos, Andrés Asensio


    The Mg II h&k lines are powerful diagnostics for studying the solar chromosphere. They have become particularly popular with the launch of the IRIS satellite, and a number of studies that include these lines have lead to great progress in understanding chromospheric heating, in many cases thanks to the support from 3D MHD simulations. In this study we utilize another approach to analyze observations: non-LTE inversions of the Mg II h&k and UV triplet lines including the effects of partial redistribution. Our inversion code attempts to construct a model atmosphere that is compatible with the observed spectra. We have assessed the capabilities and limitations of the inversions using the FALC atmosphere and a snapshot from a 3D radiation-MHD simulation. We find that Mg II h&k allow reconstructing a model atmosphere from the middle photosphere to the transition region. We have also explored the capabilities of a multi-line/multi-atom setup, including the Mg II h&k, the Ca II 854.2 nm and the Fe I ...

  15. UGC 3672: an unusual merging triplet of gas-rich galaxies in the Lynx-Cancer void (United States)

    Chengalur, J. N.; Pustilnik, S. A.; Egorova, E. S.


    We present H I 21 cm and optical observations of UGC 3672 which is located near the centre of the nearby Lynx-Cancer void. We find that UGC 3672 consists of an approximately linearly aligned triplet of gas-rich dwarfs with large-scale velocity continuity along the triplet axis. The faintest component of the triplet is extremely gas-rich M_{H I}/L_B ˜ 17) and also extremely metal deficient (12 + log (O/H) ∼ 7.0). The metallicity of this dwarf is close to the 'floor' observed in star-forming galaxies. Low-resolution H I images show that the galaxy triplet is located inside a common H I envelope, with fairly regular, disc-like kinematics. At high angular resolution however, the gas is found to be confined to several filamentary tidal tails and bridges. The linear alignment of the galaxies, along with the velocity continuity that we observe, is consistent with the galaxies lying along a filament. We argue that the location of this highly unusual system in an extremely low-density environment is not a coincidence, but is a consequence of structure formation proceeding more slowly and also probing smaller scales than in regions with average density. Our observations also indicate that wet mergers of galaxies flowing along filaments is a possible pathway for the formation of gas-rich discs. The UGC 3672 system provides an interesting opportunity to study the kind of interactions typical between high-redshift extremely gas-rich unevolved small systems that lie at base of the hierarchical galaxy formation model.

  16. Interband coulomb interaction and horizontal line nodes in triplet superconductor Sr sub 2 RuO sub 4

    CERN Document Server

    Hasegawa, Y


    A possible mechanism for appearance of the horizontal line nodes in triplet superconductor, Sr sub 2 RuO sub 4 , is proposed. We consider the interlayer Coulomb interaction, as well as the on-site Coulomb repulsion, between electrons in different bands. In the second order perturbation of the interband interaction, the effective interaction becomes dependent on cos q sub z /2, resulting in horizontal line nodes. (author)

  17. Application of the short and long consecutive pairs model to the triplet-doublet interaction in molecular crystals (United States)

    Barhoumi, T.; Monge, J. L.; Bouchriha, H.


    We have adapted the model of two consecutive pairs to the study of the triplet-doublet (T-D) interaction in molecular crystals. We have applied this model to the modulation of the photoconductivity in crystalline anthracene by a static magnetic field (MFE) and a microwave field (PDMR). We were able to reproduce, for the first time, quite perfectly two types of experiments with the same set of kinetic constants.

  18. Quantum mechanical reaction probability of triplet ketene at the multireference second-order perturbation level of theory. (United States)

    Ogihara, Yusuke; Yamamoto, Takeshi; Kato, Shigeki


    Triplet ketene exhibits a steplike structure in the experimentally observed dissociation rates, but its mechanism is still unknown despite many theoretical efforts in the past decades. In this paper we revisit this problem by quantum mechanically calculating the reaction probability with multireference-based electronic structure theory. Specifically, we first construct an analytical potential energy surface of triplet state by fitting it to about 6000 ab initio energies computed at the multireference second-order Mller-Plesset perturbation (MRMP2) level. We then evaluate the cumulative reaction probability by using the transition state wave packet method together with an adiabatically constrained Hamiltonian. The result shows that the imaginary barrier frequency on the triplet surface is 328i cm-1, which is close to the CCSD(T) result (321i cm-1) but is likely too large for reproducing the experimentally observed steps. Indeed, our calculated reaction probability exhibits no signature of steps, reflecting too strong tunneling effect along the reaction coordinate. Nevertheless, it is emphasized that the flatness of the potential profile in the transition-state region (which governs the degree of tunneling) depends strongly on the level of electronic structure calculation, thus leaving some possibility that the use of more accurate theories might lead to the observed steps. We also demonstrate that the triplet potential surface differs significantly between the CASSCF and MRMP2 results, particularly in the transition-state region. This fact seems to require more attention when studying the "nonadiabatic" scenario for the steps, in which the crossing seam between S0 and T1 surfaces is assumed to play a central role.

  19. Symmetry analysis of the vibronic States in the upper conical potential (2(3)A') of triplet. (United States)

    Viegas, Luis P; Alijah, Alexander; Varandas, António J C


    The symmetry properties of the rovibronic resonance states (Slonczewski resonances) supported by an upright conical potential are investigated. These symmetry properties lead to a useful correlation between states calculated with and without consideration of the geometrical phase, which can assist in the assignment of those states. The vibronic resonance states of triplet H3(+) (2(3)A'), which had been studied by us before, have now been assigned to spectroscopic quantum numbers.

  20. A fluorescence detected magnetic resonance investigation of the carotenoid triplet states associated with Photosystem II of isolated spinach thylakoid membranes

    CERN Document Server

    Santabarbara, S; Carbonera, D; Heathcote, P


    The carotenoid triplet populations associated with the fluorescence emission chlorophyll forms of Photosystem II have been investigated in isolated spinach thylakoid membranes by means of fluorescence detected magnetic resonance in zero field (FDMR). The spectra collected in the 680-690 nm emission range, have been fitted by a global analysis procedure. At least five different carotenoid triplet states coupled to the terminal emitting chlorophyll forms of PS II, peaking at 682 nm, 687 nm and 692 nm, have been characterised. The triplets associated with the outer antenna emission forms, at 682 nm, have zero field splitting parameters D = 0.0385 cm/sup -1/, E = 0.00367 cm/sup -1/; D = 0.0404 cm/sup -1/, E = 0.00379 cm/sup -1/ and D = 0.0386 cm/sup -1/, E = 0.00406 cm/sup -1/ which are very similar to those previously reported for the xanthophylls of the isolated LHC II complex. Therefore the FDMR spectra recorded in this work provide insights into the organisation of the LHC II complex in the unperturbed enviro...

  1. A Conserved Proline Triplet in Val-tRNA Synthetase and the Origin of Elongation Factor P

    Directory of Open Access Journals (Sweden)

    Agata L. Starosta


    Full Text Available Bacterial ribosomes stall on polyproline stretches and require the elongation factor P (EF-P to relieve the arrest. Yet it remains unclear why evolution has favored the development of EF-P rather than selecting against the occurrence of polyproline stretches in proteins. We have discovered that only a single polyproline stretch is invariant across all domains of life, namely a proline triplet in ValS, the tRNA synthetase, that charges tRNAVal with valine. Here, we show that expression of ValS in vivo and in vitro requires EF-P and demonstrate that the proline triplet located in the active site of ValS is important for efficient charging of tRNAVal with valine and preventing formation of mischarged Thr-tRNAVal as well as efficient growth of E. coli in vivo. We suggest that the critical role of the proline triplet for ValS activity may explain why bacterial cells coevolved the EF-P rescue system.

  2. Thermodynamic changes in the photoinduced proton-transfer reaction of the triplet state of safranine-T. (United States)

    Borsarelli, Claudio D; Bertolotti, Sonia G; Previtali, Carlos M


    The enthalpy and volume changes occurring in the triplet excited state proton-transfer reactions of safranine-T (SH+) in aqueous solutions at pH 4.8, 8.3, and 10.4 were investigated using time-resolved photoacoustics (TRP). The transient triplet state species were also studied using laser-flash photolysis (LFP). The LFP experiments showed the prompt formation of 3SH+ with a triplet quantum yield phiT = 0.28 between pH 4.8 and 10.4. At pH 8.3 3SH+ decays directly to the ground state. However, at pH 4.8 and 10.4, 3SH+ reacts with protons or hydroxy ions to form the dication 3SH2(2+) or the neutral 3S species, with diffusion-controlled rate constants of kH+ = 1.6 x 10(10) M(-1) s(-1), and kHO- = 2.6 x 10(10) M(-1) s(-1), respectively. Under the same experimental conditions, the TRP measurements allowed the accurate determination of the energy content of the rapidly formed triplet state 3SH+ i.e. E(T) = 175 kJ mol(-1). The slow component (0.1-3 micros) of the TRP signal at pH 4.8 and 10.4 was attributed to the formation of the species 3SH2(2+) and 3S, respectively. The enthalpy changes associated with the proton-transfer reactions of 3SH+, calculated from the values of the heat released as obtained by TRP, were in remarkable agreement with the values estimated from the thermodynamic data of the acid-base equilibria of the triplet states of the dye. The formation of 3SH+ was accompanied by a volume expansion of 1.8 cm3 mol(-1), which was explained by changes in the hydrogen-bonding interaction of the dye with its solvation sphere. Instead, the volume changes observed upon the formation of 3SH2(2-) and 3S accounted for the electrostrictive effect produced by the change in the charge distribution on the dye after the proton-transfer reaction.

  3. Analysis of spinocerebellar ataxias due to expanded triplet repeats in Greek patients with cerebellar ataxia. (United States)

    Koutsis, Georgios; Pemble, Sally; Sweeney, Mary G; Paudel, Reema; Wood, Nicholas W; Panas, Marios; Kladi, Athina; Houlden, Henry


    The relative frequency of different autosomal dominant cerebellar ataxias, commonly referred to as spinocerebellar ataxias (SCAs), varies considerably among populations of different ethnic origin. No data exist at present on the frequency of different SCAs in the Greek population. In the present study we investigated the presence of triplet repeat expansion SCAs (SCA1, SCA2, SCA3, SCA6, SCA7, SCA8, SCA12, SCA17 and DRPLA) in a cohort of 83 Greek patients with slowly progressive cerebellar ataxia. Twenty patients came from autosomal dominant (AD) pedigrees, seven displayed recessive or unclear inheritance and 56 were sporadic. We found four patients with pathological SCA expansions, all from AD pedigrees. Two patients had SCA1, one SCA2 and one SCA7 (10.0, 5.0 and 5.0% of the AD group, respectively). The clinical features of these patients were within the expected spectrum. In total, a pathological expansion was detected in 20% of patients from AD pedigrees. Interestingly, no cases of SCA3 or SCA6 were detected in the AD group. No expansions were found in other familial cases or in sporadic patients. Overall, no cases of SCA3, SCA6, SCA12, SCA17 or DRPLA were identified in the Greek population. In conclusion, SCA1, SCA2 and SCA7 are present in Greek patients with AD cerebellar ataxia in frequencies similar to those observed in other populations. SCA3 and SCA6 appear however to be rare in Greece. The genetic cause for the majority of AD ataxias remains to be identified.

  4. Magnetic proximity effect and superconducting triplet correlations at the cuprate superconductor and oxide spin valve interface (United States)

    Ovsyannikov, G. A.; Constantinian, K. Y.; Demidov, V. V.; Khaydukov, Yu. N.


    A heterostructure consisting of a cuprate superconductor YBa2Cu3O7-δ and a ruthenate/manganite (SrRuO3/La0.7Sr0.3MnO3) spin valve was studied using SQUID magnetometry, ferromagnetic resonance, and neutron reflectometry. It is shown that because of the magnetic proximity effect a magnetic moment is excited in the superconducting portion of the heterostructure, whereas the magnetic moment in the spin valve becomes suppressed. The experimentally obtained value of a typical penetration depth of a magnetic moment into the superconductor is significantly greater than the coherence length of the cuprate superconductor, which indicates that the induced magnetic moment mechanism of Cu atoms is dominant. The mesastructure prepared by adding niobium film as a second superconducting electrode to the existing heterostructure, exhibited a superconducting current (dc Josephson effect) at interlayer thicknesses that are much greater than the coherence length of the ferromagnetic materials. The maximum of the critical current density dependence on the thickness of the spin valve material corresponds to the interlayer coherence length, which agrees with the theoretical predictions associated with spin-triplet pairing. The superconducting current is observed at magnetic fields that are two orders of magnitude greater than the field corresponding to the occurrence of one magnetic flux quantum in the mesastructure. The ratio of the second harmonic of the current-phase dependence of the mesastructure superconducting current to the first, determined according to the dependence of the Shapiro steps on the amplitude of microwave exposure, did not exceed 50%.

  5. Amplification of GAA/TTC triplet repeat in vitro: preferential expansion of (TTC)n strand. (United States)

    Wu, M J; Chow, L W; Hsieh, M


    Several human hereditary neuromuscular and neurodegenerative diseases are caused by abnormal expansion of triplet repeat sequences (TRSs) CAG/CTG, CGG/CCG, or GAA/TTC on certain chromosomes. It is generally accepted that multiple slippage synthesis accounts for the instabilities of TRS. Earlier in vitro experiments by Behn-Krappa and Doerfler showed that TRS with high GC content can be expanded. In contrast, here we demonstrated that certain AT-rich TRSs, (TTC)17, (GAA)10/(TTC)10 and (GAA)17/(TTC)17, were also expansion-prone in PCR. With respect to the sequence of TRS, surprisingly, we found that the AT-rich (GAA)17/(TTC)17 extended more efficiently than the GC-rich (CAG)17/(CTG)17. This strongly suggested that the AT content of the repeat may influence TRS expansion. Furthermore, to examine the expansion of single-stranded TRS, we showed that only (TTC)17, but not the complementary (GAA)17, can be expanded. This suggested that a T-T mismatch may stabilize compatible secondary structures, most likely hairpins, for slippage synthesis. However, another poly-pyrimidine TRS, (CCT)17, is not amplification-prone in PCR. Due to the high C-content, this TRS is unlikely to adopt hairpin structures at the high pH used for PCR. Thus, the single-stranded PCR experiment may serve as an indirect assay for the ability of a sequence to adopt a hairpin conformation. When amplification was performed in reactions using Klenow DNA polymerase, only the double-stranded TRSs can be expanded. The reaction rate for (GAA)10/(TTC)10 was slower than for (GAA)17/(TTC)17, suggesting that the length of the repeat may be important for the amplification of TRS. The findings of these in vitro experiments may aid in understanding TRS expansion in vivo.

  6. Enzymatic amplification of synthetic oligodeoxyribonucleotides: implications for triplet repeat expansions in the human genome. (United States)

    Behn-Krappa, A; Doerfler, W


    The triplet repeat sequences (CGG)n, (GCT)n, and (CAG)n, which naturally occur in the human genome, can be autonomously expanded in human DNA by an as yet unknown mechanism. These in part excessive expansions have been causally related to human genetic diseases, the fragile X (Martin-Bell) syndrome, to myotonic dystrophy (Curschmann-Steinert), to spinal and bulbar muscular atrophy (Kennedy disease), and recently to Huntington disease. A GCC trinucleotide repeat was found to be expanded and methylated in the fragile site FRAXE on the human X chromosome. These findings were associated with mental retardation (Knight et al., 1993). In spinocerebellar ataxia type 1 (SCA1), a polymorphic CAG repeat was found to be unstable and expanded in individuals with that disease (Orr et al., 1993). We have demonstrated in in vitro experiments that the synthetic oligodeoxyribonucleotides (CGG)17, (CGG)12, (GCC)17, (CG)25, (CTG)17, or (CAG)17 plus (GTC)17, in the absence of added natural DNA, can be expanded with Taq polymerase in the polymerase chain reaction (PCR). Some expansion can already be detected after 4 PCR cycles. The E. coli Klenow DNA polymerase also functions in a similar amplification and expansion reaction performed at 37 degrees C without cycling. Other oligodeoxyribonucleotides, like, (CGG)7, (CGGT)13, or (TAA)17, are devoid of this property or have very low activity. The cytidine-methylated polymers (GCC)17 or (CG)25 yield expansion products of considerably reduced chain lengths. The expansion of the polymer (CGG)17 is affected by cytidine methylation to a lesser degree. A specific sequence and/or secondary structure and high CG content appear to be requirements for this expansion reaction by a possible slippage mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. VizieR Online Data Catalog: NGC 5824 calcium triplet equivalent widths (Da Costa+, 2014) (United States)

    da Costa, G. S.; Held, E. V.; Saviane, I.


    Observing time to follow up the possibility of an intrinsic [Fe/H] spread in NGC 5824 was allocated for intermediate-resolution spectroscopy of candidate red giant members on both the VLT with the FORS2 multi-object spectrograph, and on the Gemini-S telescope with the GMOS-S multi-object spectrograph. (1 data file).

  8. Chiroptical Spectroscopy (United States)

    Gurst, Jerome E.


    A brief review of the literature, and Chemical and Engineering News in particular, reveals that the determination and use of optical activity is of increasing importance in today's commercial and research laboratories. The classical technique is to measure [alpha]D using a manual or recording polarimeter to provide a single value, the specific rotation at 589 nm. A spectropolarimeter can be used to determine optical activity through the UV-Visible spectrum (Optical Rotatory Dispersion [ORD]). At wavelengths far removed from electronic absorption bands, optical activity arises from circular birefringence, or the difference in the refractive index for left- and right-circularly polarized light; i.e., nL - nR does not equal zero for chiral materials. If the optical activity is measured through an absorption band, complex behavior is observed (a Cotton Effect curve). At an absorption band, chiral materials exhibit circular dichroism (CD), or a difference in the absorption of left- and right-circularly polarized light; epsilon L minus epsilon R does not equal zero. If the spectropolarimeter is set for the measurement of CD spectra, one observes what appears to be a UV-Vis spectrum except that some absorption bands are positive while others may be negative. Just as enantiomers have specific rotations that are equal and opposite at 589 nm (sodium D line), rotations are equal and opposite at all wavelengths, and CD measurements are equal and opposite at all wavelengths. Figure 1 shows the ORD curves for the enantiomeric carvones while Figure 2 contains the CD curves. The enantiomer of carvone that has the positive [alpha]D is obtained from caraway seeds and is known to have the S-configuration while the R-enantiomer is found in spearmint oil. Figure 1. ORD of S-(+)- and R-(-)-carvones Figure 2. CD of S-(+)- and R-(-)-carvones While little can be done to correlate stereochemistry with [alpha]D values, chiroptical spectroscopy (ORD and/or CD) often can be used to assign

  9. The excited triplet (T{sub 1}) state structure and vibrational properties of 2,2'-bipyridine

    Energy Technology Data Exchange (ETDEWEB)

    Lapouge, C.; Buntinx, G. [Laboratoire de Spectrochimie Infrarouge et Raman, UMR 8516 de l' Universite et du CNRS, Centre d' Etudes et de Recherches Lasers et Applications (FR 2416 du CNRS), Bat. C5, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq (France); Poizat, O. [Laboratoire de Spectrochimie Infrarouge et Raman, UMR 8516 de l' Universite et du CNRS, Centre d' Etudes et de Recherches Lasers et Applications (FR 2416 du CNRS), Bat. C5, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq (France)], E-mail:


    The geometry of the lowest lying excited triplet state (T{sub 1}) of 2,2'-bipyridine (22BPY) was optimized by using the time-dependent density functional theory (TD-DFT) with the B3LYP functional and the SVP basis set. The T{sub 1} state is of {sup 3}B{sub u} symmetry and results from a nearly one-electron {pi}{pi}* transition from the 3b{sub g} HOMO to the 4a{sub u} LUMO. Its geometry is trans-planar and essentially characterized by a reinforcement of the interring CC bond and a quinoidal distortion of the rings. This calculated triplet structure is firmly validated by an unequivocal agreement, for four 22BPY isotopomers, between the derived theoretical vibrational frequencies and previously reported experimental time-resolved resonance Raman (TR3) spectra. Moreover, vertical transitions to the 10 lowest energy triplet states T{sub n} were calculated and the corresponding T{sub 1} state resonance Raman intensities estimated, in the short-time dynamics approximation of the Franck-Condon scattering mechanism, from the gradient of the T{sub n} potential surfaces at the T{sub 1} geometry along the totally symmetric modes. Excellent agreement with the experimental resonance Raman intensities was observed for a 4a{sub u} (LUMO) {yields} 5b{sub g} (LUMO + 3) T{sub 1} {yields} T{sub n} transition. This analysis provides a further support of the TD-DFT optimized T{sub 1} state structure of 22BPY.

  10. Electron Transfer Reaction Between Desoxyadenosine and Triplet 2-Methyl-1,4-naphthaquinone: A Laser Photolysis Study

    Institute of Scientific and Technical Information of China (English)


    @@ Introduction Electron transfer oxidation of DNA by triplet artificial photonuclease reveals a bright prospect of its application in biology and medicine. Both molecular orbital calculation and laser experiments have indicated that the homo guanine sequence should be the final localization site of photoexcited hole via long range migration within DNA[1-3]. However, the direct observation of the produced ion pairs of biomolecules especially the stabilized radical cation DNA or its components is hampered by the overwhelming transient absorption of protonated radical anion of photosensitizers, such as 2-methyl-1,4-naphthaguinonel (MQ).

  11. Synthesis of skeletally diverse alkaloid-like molecules: exploitation of metathesis substrates assembled from triplets of building blocks

    Directory of Open Access Journals (Sweden)

    Sushil K. Maurya


    Full Text Available A range of metathesis substrates was assembled from triplets of unsaturated building blocks. The approach involved the iterative attachment of a propagating and a terminating building block to a fluorous-tagged initiating building block. Metathesis cascade chemistry was used to “reprogram” the molecular scaffolds. Remarkably, in one case, a cyclopropanation reaction competed with the expected metathesis cascade process. Finally, it was demonstrated that the metathesis products could be derivatised to yield the final products. At each stage, purification was facilitated by the presence of a fluorous-tagged protecting group.

  12. $H^+ W^- Z$ contribution to the static quantities of the W boson in the context of Higgs-triplet theories

    CERN Document Server

    Tavares-Velasco, G


    We calculate the one--loop contribution from the $H^+ W^- Z$ coupling to the static electromagnetic properties of the W boson. Although this coupling is absent at the tree--level in all Higgs--doublet models, it can be induced at this order in models including Higgs--triplet representations. It is found that the $H^+ W^- Z$ contribution can be as important as those arising from other couplings including Higgs bosons, such as the standard model coupling WWH or the two--Higgs--doublet model couplings $H^+ W^- \\phi^0$ and $W W \\phi^0$, with $\\phi^0=h$, $H$ and $A$.

  13. Highly efficient greenish-blue platinum-based phosphorescent organic light-emitting diodes on a high triplet energy platform

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y. L., E-mail:; Gong, S., E-mail:; White, R.; Lu, Z. H., E-mail: [Department of Materials Science and Engineering, University of Toronto, 184 College St., Toronto, Ontario M5S 3E4 (Canada); Wang, X.; Wang, S., E-mail: [Department of Chemistry, Queen' s University, 90 Bader Lane, Kingston, Ontario K7L 3N6 (Canada); Yang, C. [Department of Chemistry, Wuhan University, Wuhan 430072 (China)


    We have demonstrated high-efficiency greenish-blue phosphorescent organic light-emitting diodes (PHOLEDs) based on a dimesitylboryl-functionalized C^N chelate Pt(II) phosphor, Pt(m-Bptrz)(t-Bu-pytrz-Me). Using a high triplet energy platform and optimized double emissive zone device architecture results in greenish-blue PHOLEDs that exhibit an external quantum efficiency of 24.0% and a power efficiency of 55.8 lm/W. This record high performance is comparable with that of the state-of-the-art Ir-based sky-blue organic light-emitting diodes.

  14. Singlet oxygen triplet energy transfer-based imaging technology for mapping protein-protein proximity in intact cells. (United States)

    To, Tsz-Leung; Fadul, Michael J; Shu, Xiaokun


    Many cellular processes are carried out by large protein complexes that can span several tens of nanometres. Whereas forster resonance energy transfer has a detection range of technology with a detection range of up to several tens of nanometres: singlet oxygen triplet energy transfer. We demonstrate that our method confirms the topology of a large protein complex in intact cells, which spans from the endoplasmic reticulum to the outer mitochondrial membrane and the matrix. This new method is thus suited for mapping protein proximity in large protein complexes.

  15. Superconducting spin-valve effect and triplet superconductivity in Co Ox/Fe1/Cu /Fe2/Cu /Pb multilayer (United States)

    Leksin, P. V.; Garif'yanov, N. N.; Kamashev, A. A.; Fominov, Ya. V.; Schumann, J.; Hess, C.; Kataev, V.; Büchner, B.; Garifullin, I. A.


    We report magnetic and superconducting properties of the modified spin-valve system CoOx/Fe1/Cu /Fe2/Cu /Pb . Introduction of a Cu interlayer between Fe2 and Pb layers prevents material interdiffusion process, increases the Fe2/Pb interface transparency, stabilizes and enhances properties of the system. This allowed us to perform a comprehensive study of such heterostructures and to present theoretical description of the superconducting spin-valve effect and of the manifestation of the long-range triplet component of the superconducting condensate.

  16. Reliable Prediction with Tuned Range-Separated Functionals of the Singlet-Triplet Gap in Organic Emitters for Thermally Activated Delayed Fluorescence (TADF)

    KAUST Repository

    Sun, Haitao


    The thermally activated delayed fluorescence (TADF) mechanism has recently attracted much interest in the field of organic light-emitting diodes (OLEDs). TADF relies on the presence of a very small energy gap between the lowest singlet and triplet excited states. Here, we demonstrate that time-dependent density functional theory (TD-DFT) in the Tamm-Dancoff Approximation can be very successful in the calculations of the lowest singlet and triplet excitation energies and the corresponding singlet-triplet gap when using nonempirically tuned range-separated functionals. Such functionals provide very good estimates in a series of 17 molecules used in TADF-based OLED devices, with mean absolute deviations of 0.15 eV for the vertical singlet excitation energies and 0.09 eV [0.07 eV] for the adiabatic [vertical] singlet-triplet energy gaps as well as low relative errors and high correlation coefficients compared to the corresponding experimental values. They significantly outperform conventional functionals, a feature which is rationalized on the basis of the amount of exact-exchange included and the delocalization error. The present work provides a reliable theoretical tool for the prediction and development of novel TADF-based materials with low singlet-triplet energetic splittings.

  17. Infrared Spectroscopy of HNO and Noh Suspended in Solid Parahydrogen (United States)

    Anderson, David T.; Ruzi, Mahmut


    The only report in the literature on the infrared spectroscopy of the parent oxynitrene NOH was performed using Ar matrix isolation spectroscopy at 10 K. In this previous study, the NOH is synthesized by co-deposition of NO/Ar and a H_2/Ar mixture that is passed through a microwave discharge to create H-atoms. The H-atoms recombine with NO in the Ar matrix to produce mostly HNO, but some NOH is produced as well. In this work we irradiate NO doped parahydrogen solids at 2 K using 193 nm radiation which is known to generate H-atoms as by-products. After the photolysis laser is stopped, we detect growth of HNO and NOH presumably due to reactions of H-atoms with NO analogous to the previous Ar matrix study. The higher energy NOH isomer is predicted by high-level calculations to be in a triplet ground electronic state. Interestingly, the infrared absorptions of NOH for the two observed vibrational modes (bend and OH stretch) display fine structure; an intense central peak with smaller peaks spaced symmetrically to both lower and higher wavenumbers. Further, the spacing between the peaks is the same for both vibrational modes. We believe this fine structure reflects the zero-field splitting of the triplet ground state of NOH (magnetic dipole-dipole interaction) and our most current results and analysis will be presented. G. Maier, H. P. Reisenauer, M. De Marco, Angew. Chem. Int. Ed. 38, 108-110 (1999). M. Fushitani and T. Momose, Low Temp. Phys. 29, 740-743 (2003). U. Bozkaya, J. M. Turney, Y. Yamaguchi, and H. F. Schaefer III, J. Chem. Phys. 136, 164303 (2012).

  18. Anion photoelectron spectroscopy of radicals and clusters

    Energy Technology Data Exchange (ETDEWEB)

    Travis, Taylor R. [Univ. of California, Berkeley, CA (United States)


    Anion photoelectron spectroscopy is used to study free radicals and clusters. The low-lying 2Σ and 2π states of C2nH (n = 1--4) have been studied. The anion photoelectron spectra yielded electron affinities, term values, and vibrational frequencies for these combustion and astrophysically relevant species. Photoelectron angular distributions allowed the author to correctly assign the electronic symmetry of the ground and first excited states and to assess the degree of vibronic coupling in C2H and C4H. Other radicals studied include NCN and I3. The author was able to observe the low-lying singlet and triplet states of NCN for the first time. Measurement of the electron affinity of I3 revealed that it has a bound ground state and attachment of an argon atom to this moiety enabled him to resolve the symmetric stretching progression.

  19. Reaction of benzophenone triplet with aliphatic amines. What a potent neurotoxin can tell us about the reaction mechanism. (United States)

    Grimm, Michelle L; Allen, William J; Finn, Meghan; Castagnoli, Neal; Tanko, James M


    A photochemical model study of benzophenone triplet ((3)BP) with the MAO-B substrate 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine [MPTP (1)] and two of it's derivatives, 1-cyclopropyl-4-phenyl-1,2,3,6-tetrahydropyridine (2) and (±)-[trans-2-phenylcyclopropyl-4-phenyl-1,2,3,6-tetrahydropyridine (3) were performed. Literature precedent and calculations reported herein suggest that the barrier to ring opening for aminyl radical cations derived from N-cyclopropyl derivatives of tertiary amines (such as MPTP) will be low. The LFP results reported herein demonstrate that pathways for the reaction of (3)BP with 1, 2, and 3 are very similar. In each instance, disappearance of (3)BP is accompanied solely by appearance of bands corresponding to the diphenylhydroxylmethyl radical and neutral radical derived from MPTP and it's two derivatives 2 and 3. These results suggest that the reaction between benzophenone triplet and tertiary aliphatic amines proceed via a simple hydrogen atom transfer reaction. Additionally these model examinations provide evidence that oxidations of N-cyclopropyl derivatives of MPTP catalyzed by MAO-B may not be consistent with a pure SET pathway.

  20. Singlet-Triplet Transition in Quantum Dots Confined by Triangular and Bowl-Like Potentials: the Effect of Electric Fields

    Institute of Scientific and Technical Information of China (English)

    SUN Lian-Liang; LI Shu-Shen


    @@ We theoretically investigate the energy spectra of two-electron two-dimensional (2e 2D) quantum dots (QDs)confined by triangular potentials and bowl-like potentials in a magnetic field by exact diagonalization in the framework of effective mass theory. An in-plane electric field is found to contribute to the singlet-triplet transition of the ground state of the 2e 2D QDs confined by triangular or bowl-like potentials in a perpendicular magnetic field. The stronger the in-plane electric field, the smaller the magnetic field for the total spin of the ground states in the dot systems to change from S = 0 to S = 1. However, the influence of anin-plane electric field on the singlettriplet transition of the ground state of two electrons in a triangular QD modulated by a perpendicular magnetic field is quite small because the triangular potential just deviates from the harmonic potential well slightly. We find that the strength of the perpendicular magnetic field needed for the spin singlet-triplet transition of the ground state of the QD confined by a bowl-like potential is reduced drastically by applying an in-plane electric field.

  1. Roles of binding energy and diffusion length of singlet and triplet excitons in organic heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Monishka Rita [Centre for Renewable Energy and Low Emission Technology, Charles Darwin University, Darwin, NT 0909 (Australia); Singh, Jai [School of Engineering and IT, Charles Darwin University, Darwin, NT 0909 (Australia)


    The influence of binding energy and diffusion length on the dissociation of excitons in organic solids is studied. The binding energy and excitonic Bohr radius of singlet and triplet excitons are calculated and compared using the dissociation energy of 0.3 eV, which is provided by the lowest unoccupied molecular orbital offset in heterojunction organic solar cells. A relation between the diffusion coefficient and diffusion length of singlet and triplet excitons is derived using the Foerster and Dexter transfer processes and are plotted as a function of the donor-acceptor separation. The diffusion length reduces nearly to a zero if the distance between donor and acceptor is increased to more than 1.5 nm. It is found that the donor-acceptor separation needs to be {<=} 1.5 nm for easy dissociation on singlet excitons leading to better conversion efficiency in heterojunction organic solar cells. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Empirical calibration of the near-IR Ca II triplet - I. The stellar library and index definition

    CERN Document Server

    Cenarro, A J; Gorgas, J; Peletier, R F; Vazdekis, A; Prada, F


    A new stellar library at the near-IR spectral region developed for the empirical calibration of the Ca II triplet and stellar population synthesis modeling is presented. The library covers the range 8348-9020 Angstrom at 1.5 Angstrom (FWHM) spectral resolution, and consists of 706 stars spanning a wide range in atmospheric parameters. We have defined a new set of near-IR indices, CaT*, CaT and PaT, which mostly overcome the limitations of previous definitions, the former being specially suited for the measurement of the Ca II triplet strength corrected for the contamination from Paschen lines. We also present a comparative study of the new and the previous calcium indices, as well as the corresponding transformations between the different systems. A thorough analysis of the sources of index errors and the procedure to calculate them is given. Finally, index and error measurements for the whole stellar library are provided together with the final spectra.

  3. Can the 750-GeV diphoton resonance be the singlet Higgs boson of custodial Higgs triplet model? (United States)

    Chiang, Cheng-Wei; Kuo, An-Li


    The observation of diphoton excess around the mass of 750 GeV in LHC Run-II motivates us to consider whether the singlet Higgs boson in the custodial Higgs triplet model can serve as a good candidate because an earlier study of comprehensive parameter scan shows that it can have the right mass in the viable mass spectra. By assuming the singlet Higgs mass at 750 GeV, its total width less than 50 GeV and imposing constraints from the LHC 8-TeV data, we identify an approximately linear region on the (vΔ , α) plane along which the exotic Higgs boson masses satisfy a specific hierarchy and have lower possible spectra, where vΔ denotes the triplet vacuum expectation value and α is the mixing angle between the singlet Higgs boson and the standard model-like Higgs boson. Although the diphoton decay rate can be enhanced by charged Higgs bosons running in the loop in this region, it is mostly orders of magnitude smaller than that required for the observed production rate, except for the small vΔ region when the diphoton fusion production mechanism becomes dominant. Nonetheless, this part of parameter space suffers from the problems of breakdown of perturbativity and large uncertainties in the photon parton distribution function of proton.

  4. Observations and Bayesian location methodology of transient acoustic signals (likely blue whales) in the Indian Ocean, using a hydrophone triplet. (United States)

    Le Bras, Ronan J; Kuzma, Heidi; Sucic, Victor; Bokelmann, Götz


    A notable sequence of calls was encountered, spanning several days in January 2003, in the central part of the Indian Ocean on a hydrophone triplet recording acoustic data at a 250 Hz sampling rate. This paper presents signal processing methods applied to the waveform data to detect, group, extract amplitude and bearing estimates for the recorded signals. An approximate location for the source of the sequence of calls is inferred from extracting the features from the waveform. As the source approaches the hydrophone triplet, the source level (SL) of the calls is estimated at 187 ± 6 dB re: 1 μPa-1 m in the 15-60 Hz frequency range. The calls are attributed to a subgroup of blue whales, Balaenoptera musculus, with a characteristic acoustic signature. A Bayesian location method using probabilistic models for bearing and amplitude is demonstrated on the calls sequence. The method is applied to the case of detection at a single triad of hydrophones and results in a probability distribution map for the origin of the calls. It can be extended to detections at multiple triads and because of the Bayesian formulation, additional modeling complexity can be built-in as needed.

  5. Pair and triplet approximation of a spatial lattice population model with multiscale dispersal using Markov chains for estimating spatial autocorrelation. (United States)

    Hiebeler, David E; Millett, Nicholas E


    We investigate a spatial lattice model of a population employing dispersal to nearest and second-nearest neighbors, as well as long-distance dispersal across the landscape. The model is studied via stochastic spatial simulations, ordinary pair approximation, and triplet approximation. The latter method, which uses the probabilities of state configurations of contiguous blocks of three sites as its state variables, is demonstrated to be greatly superior to pair approximations for estimating spatial correlation information at various scales. Correlations between pairs of sites separated by arbitrary distances are estimated by constructing spatial Markov processes using the information from both approximations. These correlations demonstrate why pair approximation misses basic qualitative features of the model, such as decreasing population density as a large proportion of offspring are dropped on second-nearest neighbors, and why triplet approximation is able to include them. Analytical and numerical results show that, excluding long-distance dispersal, the initial growth rate of an invading population is maximized and the equilibrium population density is also roughly maximized when the population spreads its offspring evenly over nearest and second-nearest neighboring sites.

  6. Xaa-Arg-Gly triplets in the collagen triple helix are dominant binding sites for the molecular chaperone HSP47. (United States)

    Koide, Takaki; Takahara, Yoshifumi; Asada, Shinichi; Nagata, Kazuhiro


    HSP47 is an essential procollagen-specific molecular chaperone that resides in the endoplasmic reticulum of procollagen-producing cells. Recent advances have revealed that HSP47 recognizes the (Pro-Pro-Gly)(n) sequence but not (Pro-Hyp-Gly)(n) and that HSP47 recognizes the triple-helical conformation. In this study, to better understand the substrate recognition by HSP47, we synthesized various collagen model peptides and examined their interaction with HSP47 in vitro. We found that the Pro-Arg-Gly triplet forms an HSP47-binding site. The HSP47 binding was observed only when Arg residues were incorporated in the Yaa positions of the Xaa-Yaa-Gly triplets. Amino acids in the Xaa position did not largely affect the interaction. The recognition of the Arg residue by HSP47 was specific to its side-chain structure because replacement of the Arg residue by other basic amino acids decreased the affinity to HSP47. The significance of Arg residues in HSP47 binding was further confirmed by using residue-specific chemical modification of types I and III collagen. Our results demonstrate that Xaa-Arg-Gly sequences in the triple-helical procollagen molecule are dominant binding sites for HSP47 and enable us to predict HSP47-binding sites in homotrimeric procollagen molecules.

  7. The photospheric solar oxygen project: IV. 3D-NLTE investigation of the 777 nm triplet lines

    CERN Document Server

    Steffen, M; Caffau, E; Ludwig, H -G; Bonifacio, P; Cayrel, R; Kučinskas, A; Livingston, W C


    The solar photospheric oxygen abundance is still widely debated. Adopting the solar chemical composition based on the "low" oxygen abundance, as determined with the use of three-dimensional (3D) hydrodynamical model atmospheres, results in a well-known mismatch between theoretical solar models and helioseismic measurements that is so far unresolved. We carry out an independent redetermination of the solar oxygen abundance by investigating the center-to-limb variation of the OI IR triplet lines at 777 nm in different sets of spectra with the help of detailed synthetic line profiles based on 3D hydrodynamical CO5BOLD model atmospheres and 3D non-LTE line formation calculations with NLTETD. The idea is to simultaneously derive the oxygen abundance,A(O), and the scaling factor SH that describes the cross-sections for inelastic collisions with neutral hydrogen relative the classical Drawin formula. The best fit of the center-to-limb variation of the triplet lines achieved with the CO5BOLD 3D solar model is clearly...

  8. Hybrid-Thresholding based Image Super-Resolution Technique by the use of Triplet Half-Band Wavelets (United States)

    Chopade, Pravin B.; Rahulkar, Amol D.; Patil, Pradeep M.


    This paper presents a modified image super-resolution scheme based on the wavelet coefficients hybrid-thresholding by the use of triplet half-band wavelets (THW) derived from the generalized half-band polynomial. At first, discrete wavelet transform (DWT) is obtained from triplet half-band kernels and it applied on the low-resolution image to obtain the high frequency sub-bands. These high frequency sub-bands and the original low-resolution image are interpolated to enhance the resolution. Second, stationary wavelet transform is obtained by using THW, which is employed to minimize the loss due to the use of DWT. In addition, hybrid thresholding scheme on wavelet coefficients scheme is proposed on these estimated high-frequency sub-bands in order to reduce the spatial domain noise. These sub-bands are combined together by inverse discrete wavelet transform obtained from THW to generate a high-resolution image. The proposed approach is validated by comparing the quality metrics with existing filter banks and well-known super-resolution scheme.

  9. Accurate adiabatic singlet-triplet gaps in atoms and molecules employing the third-order spin-flip algebraic diagrammatic construction scheme for the polarization propagator (United States)

    Lefrancois, Daniel; Rehn, Dirk R.; Dreuw, Andreas


    For the calculation of adiabatic singlet-triplet gaps (STG) in diradicaloid systems the spin-flip (SF) variant of the algebraic diagrammatic construction (ADC) scheme for the polarization propagator in third order perturbation theory (SF-ADC(3)) has been applied. Due to the methodology of the SF approach the singlet and triplet states are treated on an equal footing since they are part of the same determinant subspace. This leads to a systematically more accurate description of, e.g., diradicaloid systems than with the corresponding non-SF single-reference methods. Furthermore, using analytical excited state gradients at ADC(3) level, geometry optimizations of the singlet and triplet states were performed leading to a fully consistent description of the systems, leading to only small errors in the calculated STGs ranging between 0.6 and 2.4 kcal/mol with respect to experimental references.

  10. Sulphur abundances in halo giants from the [S ı] line at 1082 nm and the [S ı] triplet around 1045 nm

    DEFF Research Database (Denmark)

    Jönsson, H.; Ryde, N.; Nissen, Poul Erik;


    to clarify this situation by measuring the sulphur abundance in a sample of halo giants using two diagnostics: the S i triplet around 1045 nm and the [S i] line at 1082 nm. The latter of the two is not believed to be sensitive to non-LTE effects. We can thereby minimize the uncertainties in the diagnostic...... used and estimate the usefulness of the triplet for the sulphur determination in halo K giants. We will also be able to compare our sulphur abundance differences from the two diagnostics with the expected non-LTE effects in the 1045 nm triplet previously calculated by others. Methods. High......Context. It is still debated whether or not the Galactic chemical evolution of sulphur in the halo follows the flat trend with [Fe/H] that is ascribed to the result of explosive nucleosynthesis in type II SNe. It has been suggested that the disagreement between different investigations of sulphur...

  11. A model for the [C+-GxC]n triple helix derived from observation of the C+-GxC base triplet in a crystal structure. (United States)

    Nunn, C M; Trent, J O; Neidle, S


    A molecular modelling study on the [C+-GxC]n triple helix is reported. We have observed the C+-GxC base triplet in the crystal structure of an oligonucleotide-drug complex, between the minor-groove drug netropsin and the decanucleotide d(CGCAATTGCG)2. The complex was crystallised at pH 7.0, but the crystal structure, at a resolution of 2.4 A, shows that a terminal cytosine has become protonated and participates in a parallel C+-GxC base triplet. The structure of this triplet and its associated sugar-phosphate backbones have been energy-refined and then used to generate a triple helix. This has characteristics of the B-type family of DNA structures for two strands, with the third, the C+ strand, having backbone conformations closer to the A family.

  12. The photophysics of monomeric bacteriochlorophylls c and d and their derivatives: properties of the triplet state and singlet oxygen photogeneration and quenching (United States)

    Krasnovsky, A. A. Jr; Cheng, P.; Blankenship, R. E.; Moore, T. A.; Gust, D.


    Measurements of pigment triplet-triplet absorption, pigment phosphorescence and photosensitized singlet oxygen luminescence were carried out on solutions containing monomeric bacteriochlorophylls (Bchl) c and d, isolated from green photosynthetic bacteria, and their magnesium-free and farnesyl-free analogs. The energies of the pigment triplet states fell in the range 1.29-1.34 eV. The triplet lifetimes in aerobic solutions were 200-250 ns; they increased to 280 +/- 70 microseconds after nitrogen purging in liquid solutions and to 0.7-2.1 ms in a solid matrix at ambient or liquid nitrogen temperatures. Rate constants for quenching of the pigment triplet state by oxygen were (2.0-2.5) x 10(9) M-1 s-1, which is close to 1/9 of the rate constant for diffusion-controlled reactions. This quenching was accompanied by singlet oxygen formation. The quantum yields for the triplet state formation and singlet oxygen production were 55-75% in air-saturated solutions. Singlet oxygen quenching by ground-state pigment molecules was observed. Quenching was the most efficient for magnesium-containing pigments, kq = (0.31-1.2) x 10(9) M-1 s-1. It is caused mainly by a physical process of singlet oxygen (1O2) deactivation. Thus, Bchl c and d and their derivatives, as well as chlorophyll and Bchl a, combine a high efficiency of singlet oxygen production with the ability to protect photochemical and photobiological systems against damage by singlet oxygen.

  13. Photochemical properties of C 60. Triplet-excited C 60 quenching by electron acceptors TCNQ and TCNE in solution. Laser photolysis study (United States)

    Nadtochenko, Victor A.; Denisov, Nikolai N.; Rubtsov, Igor V.; Lobach, Anatolii S.; Moravskii, Alexander P.


    The quenching of triplet-excited 3C 60 by electron acceptors TCNQ and TCNE has been established in nonpolar toluene and moderately polar benzonitrile solutions. The quenching constants kq are 5.5 × 10 9 in toluene, 2.2 × 10 9 in benzonitrile for TCNQ and 7.9 × 10 5 in toluene, 4.2 × 10 8 (M s) -1 in benzonitrile for TCNE. The 3C 60 quenching can be explained by triplet exciplex formation. The time-resolved spectra of the C 60/TCNE system exhibit a well pronounced charge-transfer excited state [C δ60 … TCNE δ-] in benzonitrile.

  14. Spin-orbit coupling and paramagnetic relaxation in micellized triplet radical pairs. Determination of relaxation parameters from magnetic field dependences of the decay kinetics (United States)

    Levin, P. P.; Kuzmin, V. A.


    The geminate recombination kinetics of the radical pairs produced by quenching of triplet benzophenone or 4-bromobenzophenone by 4-phenylphenol and 4-phenylaniline in aqueous micellar solutions of sodium dodecyl sulfate has been examined using the laser flash technique. Application of an external magnetic field results in the retardation of geminate recombination up to 20 times. The magnetic field dependences are considered in terms of a simple kinetic scheme, which includes the singlet-triplet evolution in the separated states of a pair due to hyperfine coupling and relaxation mechanisms as well as intersystem recombination process due to the spin-orbit coupling in the contact states of a pair.

  15. A kinetically blocked 1,14:11,12-dibenzopentacene: A persistent triplet diradical of a non-Kekulé polycyclic benzenoid hydrocarbon

    KAUST Repository

    Li, Yuan


    The synthesis of high-spin polycyclic hydrocarbons is very challenging due to their extremely high reactivity. Herein, we report the synthesis and characterization of a kinetically blocked 1,14:11,12-dibenzopentacene, DP-Mes, which represents a rare persistent triplet diradical of a non-Kekulé polycyclic benzenoid hydrocarbon. In contrast to its structural isomer 1,14:7,8-dibenzopentacene (heptazethrene) with a singlet biradical ground state, DP-Mes is a triplet diradical as confirmed by ESR and ESTN measurements and density functional theory calculations. DP-Mes also displays intermolecular antiferromagnetic spin interactions in solution at low temperature. © 2014 the Partner Organisations.

  16. Spectroscopy of ultracold LiRb molecules using ionization detection (United States)

    Altaf, Adeel

    We present spectroscopic studies of ultracold LiRb molecules using ionization detection. The molecules are created by cooling and trapping Li and Rb atoms in overlapping magneto-optical traps (MOTs) and using light resonant with a free-bound transition to create weakly bound excited state molecules in a process known as photoassociation (PA). We explore weakly bound vibrational levels of LiRb with PA spectroscopy using ionization detection and, where possible, compare our results with earlier measurements performed in our lab using trap-loss spectroscopy. In addition, we also probe vibrational levels of the ground triplet electronic state and excited electronic states using resonantly enhanced multiphoton ionization (REMPI) spectroscopy. We identify several vibrational levels of the alpha3Sigma+, (3)3piO and (4)3Sigma + states and compare our observations with theoretical calculations. As LiRb is one of the least studied heteronuclear diatomic molecules, these studies are aimed towards exploring the molecular structure. The spectroscopic work is also in line with the long-term project goals of transferring ultracold LiRb molecules into the lowest rotational and vibrational levels of the ground singlet electronic state. Molecules in this rovibronic ground state possess a large electric dipole moment, which is essential for application of ultracold molecules in various quantum computation schemes. The rovibronic ground state will also be an ideal starting point for investigating molecular entangled states.

  17. Triplet-triplet annihilation process in organic light-emitting diodes doped with fluorescent dyes%三重态激子在不同荧光染料掺杂体系中的湮灭过程

    Institute of Scientific and Technical Information of China (English)

    阚敏; 陈平; 曹绍谦; 刘文利; 宋群梁; 熊祖洪


    室温下,在红色荧光染料掺杂的有机发光器件ITO/N,N'-bis(naphthalen-1-y)-N,N'-bis(phenyl)benzidine (NPB)/tris(8-hydroxyquinolato) aluminum (Alq3):4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran(DCM),Alq3/LiF/A1中,观察到发光随外磁场的变化(即磁致发光)表现为刚开始的快速增加,在~50 mT处达到最大后,随着磁场的进一步增加,又呈现出减弱的特点(即高场效应);而且,器件的掺杂浓度越高、所加偏压越大,该高场减弱就越明显.但在另一类绿色荧光染料5,12-dihydro-5,12-dimethylquino [2,3-b]acridine-7,14-dione (DMQA)的掺杂器件中,磁致发光的高场部分则是在~50 mT后增加变缓并逐渐趋于饱和.分析结果表明,F(o)rster能量转移过程占主导发射的DMQA掺杂器件,不利于染料分子上三重态激子的形成,从而,通过三重态激子对(triplet pairs)湮灭产生单重态激子(triplet-triplet annihilation,TTA)的过程不易发生;但在载流子陷阱效应参与发射的DCM掺杂器件中,室温下在染料分子上就可以形成寿命较长的三重态激子,增加了发生TTA过程的几率.因此,基于掺杂器件中两种不同的发射机制,外加磁场对有机发光中三重态激子对(T…T)的演化表现出了不同的调控作用.

  18. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J


    This series describes selected advances in the area of atomic spectroscopy. It is primarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  19. Basic molecular spectroscopy

    CERN Document Server

    Gorry, PA


    BASIC Molecular Spectroscopy discusses the utilization of the Beginner's All-purpose Symbolic Instruction Code (BASIC) programming language in molecular spectroscopy. The book is comprised of five chapters that provide an introduction to molecular spectroscopy through programs written in BASIC. The coverage of the text includes rotational spectra, vibrational spectra, and Raman and electronic spectra. The book will be of great use to students who are currently taking a course in molecular spectroscopy.

  20. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J


    This series describes selected advances in the area of atomic spectroscopy. It is promarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.